What is beleived to be wreckage from crashed AirAsia flight QZ8501 in the Java Sea is pictured in this underwater photograph.

The tail of a crashed AirAsia jet has been found, Indonesia's search and rescue agency said on Wednesday.

It was found on the sea bed about 30 km (20 miles) from the plane's last known location.

The discovery on the seabed could mark a breakthrough in the search as the tail of a plane usually houses the "black box" flight data recorders.

Flight QZ8501 vanished from radar screens over the northern Java Sea on Dec 28.

Despite a huge recovery operation assisted by various countries, progress has been patchy with poor weather conditions hampering the search.

A member of an Indonesian search and rescue team scans the sea for debris from AirAsia flight QZ8501.

Personal effects from passengers recovered from search operations in the Java Sea of AirAsia flight QZ8501 are displayed upon arrival at Juanda military airport in Surabaya on January 7, 2015.

Indonesian military personnel carry coffins of victims recovered from the ill-fated Malaysian air carrier AirAsia flight QZ8501, upon their arrival at the military airbase in Surabaya, East Java on December 31, 2014.

Indonesian Search and Rescue crews unload one of two bodies of AirAsia passengers recovered from sea at the airport in Pangkalan Bun, central Kalimantan.

Search and rescue team members run as they carry the dead body of a passenger onboard AirAsia flight QZ8501 at Iskandar airbase in Pangkalan Bun, Indonesia, December 31, 2014.

Indonesian President Joko Widodo (L) standing in the cockpit of an Air force aircraft Hercules C-130 during the search and locate (SAL) operation for missing AirAsia flight QZ8501.

Crew member of an Indonesian Maritime Surveillance plane says a prayer before a search mission to look for AirAsia's Flight QZ8501 in Pangkal Pinang.

Members of the Indonesia marines unload their diving equipment as they arrive at Pangkalan Bun air base in Central Kalimantan.

A family member of passengers onboard the missing Malaysian air carrier AirAsia flight QZ8501, reacts after seeing an unidentified floating dead body during a search and rescue mission.

An Indonesian warship recovered more than 40 bodies from the sea Tuesday in the search for the AirAsia jet, a navy spokesman told AFP.

"Based on the navy radio, it has been reported that the warship Bung Tomo has retrieved 40 bodies and the number is growing. They are very busy now," Manahan Simorangkir said.

Earlier, Indonesia's media outlets reported that Indonesian warship KRI Bung Tomo has found six bodies, and retrieved three, citing local broadcaster TV One.

Relatives of the 162 people missing on the plane hugged each other and burst into tears in Surabaya, where the missing Indonesia AirAsia flight QZ8501 plane departed from, as they watched footage showing a body floating in the sea on a television feed of a press conference in Jakarta.

AirAsia Indonesia president director Sunu Widiyatmoko said the airline would ready a 180-seat Airbus 320 for families of the missing AirAsia passengers on Wednesday.

"This is aimed at keeping the families informed in detail about the joint search operation being conducted," he told journalists at the AirAsia Crisis Center at Terminal II of Juanda International Airport in Surabaya on Tuesday.

"The aircraft carrying the passengers' families will fly around the search location before returning to Surabaya," he said.

On Tuesday, the Transportation Ministry's acting director general of air transportation, Djoko Murjatmodjo, confirmed that wreckage discovered in Pangkalan Bun, Central Kalimantan, was from AirAsia flight QZ8501.

"It has been confirmed that it is debris from an aircraft bearing red and white colors," Djoko said, citing that the debris had been found by the ministry's rescue team.

"The recovery process will now be centered on the debris location, in coordination with Basarnas [National Search and Rescue Agency]," he said.

State airport operator PT Angkasa Pura (AP) I president director Tomi Sutomo said the flight transporting the AirAsia passengers' families would be coordinated with Basarnas.

"We don't want to disrupt the ongoing search operation, so we will hand over the technical matters of the flight to Basarnas," said Tomi.

Air Force Hercules C130 co-pilot Lt. Tri Wibowo, who flew on Tuesday over waters near Pangkalan Bun in Central Kalimantan in the search for missing AirAsia flight QZ8501, said that he saw dozens of floating bodies as well as bags and aircraft debris.

"We thought that the passengers were still alive and waved at us for help. But when we approached closer [we saw] they were already dead," said Tri as quoted by kompas.com.

Tri and the team scoured the area at around 11 am.

The Transportation Ministry earlier confirmed that white and red debris found near Pangkalan Bun belonged to the ill-fated flight, which vanished on Sunday en route to Singapore from Indonesia's second-biggest city of Surabaya in East Java.

The aircraft was carrying 162 people.

Basarnas reported that it had found 10 pieces of debris during its search for the ill-fated AirAsia Indonesia aircraft southwest of Pangkalan Bun in Central Kalimantan.

Basarnas spokesman M. Yusuf Latif said on Tuesday that a CN maritime patrol aircraft from the Indonesian Air Force first discovered the debris during a search on Tuesday morning.

"We just searched [the location] until 11 am. So, according to estimations, the debris was seen at 10:15 a.m.," he told reporters at the agency's headquarters in Kemayoran, Central Jakarta.

The location of the debris matched information from two fishermen in Pangkalan Bun who said that they heard a thud and saw explosions on Sunday morning, Yusuf said.

Family members of passengers onboard missing Malaysian air carrier AirAsia flight QZ8501 pray together while waiting for a briefing inside the crisis-centre set up at Juanda International Airport in Surabaya on Dec 30, 2014.

Indonesia's National Search and Rescue Agency chief said Tuesday that just three bodies had been recovered so far in the search for the AirAsia plane which crashed in the Java Sea, after another official said 40 had been found.

"Today we evacuated three bodies and they are now in the warship Bung Tomo," Bambang Soelistyo told a news conference in Jakarta, adding that they were two females and one male.

Some of the debris that was found by search and rescue aircraft.

Navy spokesman Manahan Simorangkir told AFP earlier that according to naval radio a warship had recovered more than 40 bodies from the sea. But he later said that report was a miscommunication by his staff.

The Airbus A320-200 carrying 162 people crashed Sunday en route from Indonesia's second largest city Surabaya to Singapore, with wreckage recovered near its last known location.

Government security officials carry of a family member of passengers onboard AirAsia flight QZ8501 after she collapsed at a waiting area in Juanda International Airport, Surabaya, Dec 30, 2014.

Members of the Indonesian air force show items retrieved from the Java sea during search and rescue operations for the missing AirAsia flight QZ8501.

A member of the Indonesian air force carries an item retrieved from the Java sea during search and rescue operations for the missing AirAsia flight QZ8501.

Members of the Indonesian air force carry items retrieved from the Java sea during search and rescue operations for the missing AirAsia flight QZ8501.

A family member of passengers onboard the missing Malaysian air carrier AirAsia flight QZ8501 receives medical assistance after watching news reports showing an unidentified body floating in the Java sea.

Indonesian President Joko Widodo said the primary focus of the search mission now was to retrieve the bodies of the remaining passengers and crew members of the doomed Indonesia AirAsia Flight QZ8501

Stormy weather Wednesday forced Indonesian rescuers to suspend their search for the bodies of those on AirAsia's Flight QZ8501

Indonesian students pray for victims of the missing AirAsia flight QZ8501 in Tangeran

A message board has been set up at the Changi Airport for the public to express their thoughts to families and friends of the passengers aboard the ill-fated Indonesia AirAsia Flight QZ8501.

An Indonesian search and rescue aircraft over the Java Sea spotted floating debris

in the same area as other items being investigated by Indonesian authorities as possible objects from missing AirAsia flight QZ8501

Items resembling an emergency slide, plane door and other objects were spotted during an aerial search for the missing AirAsia plane

Servicemen of Singapore Navy board the Formidable-class frigate RSS Supreme, as they are deployed in support of the search & locate operation for the missing AirAsia flight QZ8501.

Speaking with Republic of Singapore Navy (RSN) servicemen on board RSS Supreme before departing for Indonesia to take part in the search and locate (SAL) operation for missing AirAsia flight.

F. H. Bambang Soelistyo (a 3-star air force officer) points to the estimated located where the ill-fated AirAsia plane was last detected by radar on Sunday.

At Soekarno-Hatta Airport Terminal 3 in Jakarta at about 1.30am on Dec 29.

A relative shows a picture of alleged passengers who were travelling on missing Malaysian air carrier AirAsia flight QZ8501 on her mobile phone screen at the airport.

AirAsia CEO Tony Fernandes talks with director Sunu Widyatmoko during a news conference.

AirAsia CEO Tony Fernandes walks in front of family members of passengers onboard the missing AirAsia Flight QZ8501 at a news conference.

Indonesian President Joko Widodo (C), accompanied by (L to R) military commander General Moeldoko, Navy Chief Admiral Marsetio, Air Chief Marshal Ida Bagus Putu Dunia and Coordinating Political, Legal and Security Affairs Minister Tedjo Edhy Purdijatno.

2 members of the Indonesian Navy's Tactical Commanding Operator (TACCO) help with the search for flight QZ8501 on board a CN235 aircraft.

Monitoring progress in the search for Flight QZ8501 during a visit to the National Search and Rescue Agency in Jakarta.

Air Asia flight QZ8501 from Surabaya to Singapore went missing on Sunday morning (December 28, 2014).

Next of kin were ushered from Terminal 1 to a holding area in Terminal 2. About a dozen family members are believed to be inside the room.

A waiting area for relatives has been set up.

Another family of 4 has gone into the holding area at Changi Airport, where next of kin of passengers have been waiting since 9.30am.

A waiting area for relatives has been set up in Changi Airport Terminal 2.

Family members of passengers of missing Malaysian air carrier AirAsia flight QZ8501 gather at Juanda international airport in Surabaya in East Java after the news the flight went missing.

The AirAsia Airbus plane with 162 people on board went missing en route from Indonesia to S'pore early on Dec 28.

AirAsia flight QZ8501 bound for Singapore from the Indonesian city of Surabaya was lost on Sunday morning.

Unnamed family members of passengers on board the missing flight.

A sign informing next-of-kins of passengers of flight QZ8501.

Flight timeline of QZ8501.

Transport Minister Lui Tuck Yew said that Changi Airport Group has opened a holding area for relatives of the missing passengers.

Tony Fernandes.

Flight tracking website, Flightradar24.com said that the missing airline did not send out any distress signals before losing contact.

QZ8501's flight plan according to Flightradar24.com.

Malaysia PM Najib says his thoughts are with AirAsia in facing this crisis.

PM Lee says Singapore will stand with Indonesia in facing this crisis and is ready to offer help where possible.

Defence Minister Ng Eng Hen says Singapore will offer assistance in search and rescue efforts.

The Civil Aviation Authority of Singapore.

The first statement from AirAsia on its Facebook page.

Upon learning of the tragedy, AirAsia immediately changed its striking red logo to a grey one on its social media sites.

Officials mapping out the flight route.

Louise Sidharta, 25 whose fiance was on the missing flight speaking to the media outside the holding rom for relatives and next-of-kin at Changi Airport Terminal 2, Dec 28, 2014.

A search and rescue squad from the Indonesian Airforce prepare to depart on a Puma helicopter to take part in the search for the missing AirAsia Flight QZ8501, from a base in Kubu Raya, West Kalimantan.

Director general of civil aviation Djoko Murjatmodjo (C) briefs journalists during a press conference in Jakarta

An unidentifed relative of a passenger on board AirAsia flight QZ8501 bound for Singapore leaves the holding area at Changi international airport terminal in Singapore on December 28, 2014

Family members of passengers on board AirAsia flight QZ 8501wait for information inside a crisis centre at Juanda Airport in Surabaya, East Java

An official from Indonesia's national search and rescue agency in Medan, North Sumatra points at his computer screen to the position where AirAsia flight QZ8501 went missing off the waters of Indonesia on December 28, 2014

Andri Hadi,Indonesian Ambassador to Singapore arriving at the holding room in Changi Airport Terminal 2