Tokyo: Outspoken Japanese politician Taro Aso has offended the main opposition party with a comment about Nazis, days after winning a senior post in the ruling party that could help him become prime minister.

Aso, who missed out on becoming prime minister in a Liberal Democratic Party (LDP) leadership vote last year, is a frontrunner to win the top job if unpopular Prime Minister Yasuo Fukuda cannot improve his voter ratings.

Shifting away

Upper house speaker Satsuki Eda of the opposition Democratic Party told Aso in a meeting that the electorate was shifting away from the LDP, the Nikkei financial daily and other papers said.

Apparently irritated, Aso told Eda: "If you look at history, you will see that as a result of the people moving away from the party of government, regimes like the Nazis have come into power," the Nikkei reported.

Yukio Hatoyama, Democratic Party secretary-general, called for an apology.

"This is very abusive language," he told reporters. "He should apologise."

Aso said he hoped Eda had not disclosed his comments to the public intentionally.

No intention

"I don't want to think that the speaker disclosed them on purpose, and I don't have any intention of comparing the Democrats to the Nazis," he told a news conference.

An official from Aso's office confirmed he had referred to Nazis but played down the significance of it.

"He was saying that the fact that debate has not been progressing in parliament is a serious problem and that the Nazi regime arose from a similar situation," said the staff member, who declined to be identified.