The conservative leader, who has campaigned to build a nation prouder of its past, noted that his grandfather, former prime minister Nobusuke Kishi, was also unpopular while in office.

"Support rates were also fairly low for my grandfather but I believe he is now appreciated highly," Abe said in a group interview with sports newspapers conducted Tuesday.

"It is true that evaluations of politicians are formed gradually after their coffins are closed," he said, as quoted by the Nikkan Sports paper.

Quoting another former conservative prime minister, Yasuhiro Nakasone, Abe said that politicians "are tried in a court called history."

Abe, who took office in September as Japan's first prime minister born after World War II, has pushed to shake off legacies of defeat, including by rewriting the US-imposed 1947 pacifist constitution.

But his support rate has sunk below 30 percent in recent weeks amid a series of scandals and gaffes involving top ministers, including one who committed suicide.

Abe would likely face pressure to resign if his coalition fares poorly in July 29 elections for the upper house of parliament.

Abe's maternal grandfather Kishi fought widespread protests by leftists during his 1957-1960 tenure as premier as he built a new alliance with the United States.