Prime Minister Shinzo Abe on Wednesday pledged to make an all-out effort for the rest of his term to deliver on his main goals of beating deflation and revising the nation's pacifist Constitution as he became the longest-serving prime minister in Japanese history.

Abe, who returned to power in 2012, broke the previous record set by Taro Katsura over a century ago as Wednesday marked his 2,887th day in office, including a short 2006-2007 stint.

"I still have nearly two years left in my term as president of the Liberal Democratic Party. Under the weight of my responsibility, I will make an all-out effort to tackle policy goals, remembering the time when I first started out feeling nervous as if walking on thin ice," Abe told reporters at his office.

Abe becomes longest-serving Japan prime minister, legacy in focus

The key items on his agenda include declaring an end to deflation, tackling the issue of the country's aging population coupled with a declining birth rate and resolving diplomatic challenges left unaddressed since the end of World War II, Abe said.

"Beyond that, revising the Constitution is also on the horizon," he said.

The 65-year-old leader has yet to make substantive progress in the Diet toward amending the supreme law for the first time since it entered into force in 1947.

Economic growth is also seen fragile despite years of "Abenomics," a program that includes bold monetary easing by the Bank of Japan to enable the nation to emerge from deflation.

Still, Abe has received relatively stable public support in the absence of a viable opposition bloc. With no apparent contenders waiting in the wings, some LDP lawmakers, including Secretary General Toshihiro Nikai, have expressed support for Abe's potential bid for another term.

Abe is believed to be reluctant to seek another term as LDP head beyond September 2021. Under LDP rules, the current term should be his last.