LIMA -- Japan's embattled Prime Minister Taro Aso on Friday bowed to criticism of his brief tenure in office but lashed out at the opposition for boycotting key debates in parliament.

"I have faced a lot of criticism. I would like to accept the criticism sincerely and humbly," Aso told reporters in Peru, where he is attending a summit of Asia-Pacific leaders.

Aso, who took office in September, most recently came under fire for criticizing the medical profession, saying that many doctors lacked basic common sense. He later apologized.

The outspoken conservative was also forced to retract remarks hinting at a review of privatization of the postal service -- a key achievement of former reformist premier Junichiro Koizumi -- as he had not consulted his party on the sensitive matter.

The Aso government's approval rating has already plunged below 30 percent, emboldening the opposition which is pushing him to call snap elections.

But Aso denounced the opposition, which controls one house of parliament, for refusing to begin debate on a bill to allow the government to inject public funds into small banks in the world's second largest economy.

"How long does the opposition want to refuse to vote?" Aso asked. "The law on strengthening finances is significant. I'm sure the public will see a big impact if they go all the way with the opposition."

He remained tight-lipped on elections, which must be called by September 2009, saying: "I have not yet decided what should be the deciding factor."

Aso's Liberal Democratic Party has been in power for all but 10 months since 1955 but has gone through four prime ministers in the past two years amid a string of scandals, a troubled economy and legislative deadlock.