SYDNEY - Prime Minister Tony Abbott on Monday warned Australians fighting with extremist groups in the Middle East they face lengthy jail terms if they return home.
"My unambiguous message to all Australians who fight with terrorist groups is that you will be arrested, prosecuted and jailed for a very long time," Abbott told parliament in a statement on national security.
Australia has announced tougher counter-terrorism laws to target home-grown terrorists and those who fight overseas over fears violent jihadist citizens in Syria and Iraq will return home.
"Our laws are being changed to make it easier to keep potential terrorists off our streets," Abbott said after the biggest security crackdown in Australian history last Thursday saw more than 800 police officers raid nearly 30 homes.
A 22-year-old man was charged with planning a terrorist act.
The government said it had foiled a plot by Islamic State jihadists to carry out gruesome "demonstration executions" in Australia.
Abbott said 60 Australians were known to be fighting in Iraq and Syria, 20 had already returned to Australia while another 100 actively support the jihadists.
The government says current legislation is inadequate to fight the threats from groups such as the Islamic State and is pushing two bills through parliament this week.
"Legislation to create new terrorist offences and to extend existing powers to monitor or to detain terror suspects will be introduced this week," the prime minister said.
"As well, legislation requiring telecommunications providers to keep the metadata they already create and to continue to make it available to police and security agencies will be introduced soon."
Attorney-General George Brandis has drawn up a bill to give security agencies greater powers and another bill to deal with the threat from so-called "foreign fighters" returning from combat with extremists abroad.
Under the new powers, which are expected to have broad bi-partisan support, it will be illegal for an individual to intentionally counsel, promote, encourage or urge a terrorist act, Brandis said.
The bills will also allow for bans on visits to cities or regions where terror groups are declared to be active. People travelling to such "no-go areas" without a valid reason could face prosecution.
Abbott regretted that "for some time to come, Australians will have to endure more security than we're used to, and more inconvenience than we'd like".
"Creating new offences that are harder to beat on a technicality may be a small price to pay for saving lives and for maintaining the social fabric of an open, free and multicultural nation," he said.
The government has earmarked an additional Aus$630 million (S$713.11 million) to bolster security and stepped up protection at public places across the country, including parliament.
Canberra has also committed 600 troops and aircraft to the US-led coalition gearing up to destroy the IS organisation in Iraq.