Prime Minister Shinzo Abe was reelected unopposed as president of the Liberal Democratic Party without a vote Tuesday, the day the election was officially announced.
The LDP will later hold a general meeting of party lawmakers of both chambers of the Diet to formalize Abe's reelection.
It was the first time in 14 years - since the reelection in 2001 of then Prime Minister Junichiro Koizumi - that the LDP president has been reelected without a vote.
Seiko Noda, former chief of the LDP General Council, had sought to run against Abe in the leadership race but failed to secure the recommendations of 20 LDP lawmakers required to file a candidacy.
"Abenomics is still half-finished," Abe told reporters at the Prime Minister's Office after his reelection. "We'll deliver a virtuous cycle of economic recovery to every corner of the country, advance the vitalization of local economies and accelerate reconstruction."
He stressed that he will fulfil his responsibility by tackling various tasks and achieving results.
Referring to his uncontested reelection, Abe said, "I believe many [LDP] lawmakers thought they would unite to fulfil pledges [made during the House of Representatives election in December last year]."
Abe's new term as the LDP president runs until the end of September 2018. This is the third time for him to win the LDP presidency. He was the LDP president during his first Cabinet in 2006.
Abe is scheduled to visit the United States late this month to attend the UN General Assembly. He is expected to reshuffle his Cabinet and the LDP executive lineup in early October after returning from his trip.
During an election rally at a Tokyo hotel on Tuesday morning, Abe said his administration would continue to place top priority on the economy. "We'll completely overcome deflation via a virtuous economic cycle and achieve powerful economic growth," he said.
Abe incorporated economic revitalisation, measures to deal with the shrinking population and constitutional amendment in his pledges for the LDP presidential election campaign.
Noda expresses regret
Meanwhile, Noda announced on the day that she would not run in the race.
"I tried to run, but gave up," she said at a press conference held in the Diet Building at about 8 a.m.
Noda was seeking support from lawmakers close to her until the last minute to avoid Abe's reelection without a vote.
However, Noda was not able to gain the support of other lawmakers as all seven intraparty factions backed Abe's reelection.
At the press conference, Noda expressed regret, saying she wanted to hold an open LDP presidential election to give peace of mind "to people who are anxious about the party."
The press conference was also attended by Hidehisa Otsuji, former vice president of the House of Councillors, who was to become representative of Noda's recommenders.
Noda did not clarify how many recommendations from lawmakers she received, but said, "As I don't have my own faction or group, I received a miracle number."