In a surprise move, former Foreign Minister Makiko Tanaka on Friday tendered her resignation to the House of Representatives in an apparent move to take responsibility for allegations that she misappropriated her secretaries' salaries.

The resignation was submitted to Lower House Speaker Tamisuke Watanuki just before noon at his official residence. Watanuki later approved the resignation, according to the secretariat of the Lower House.

Later Friday, Tanaka told reporters outside her Tokyo home that she first considered resigning from the Diet when the Liberal Democratic Party handed her a two-year suspension June 20, effectively booting her out of the party.

The LDP's Ethics Committee decided to suspend Tanaka as punishment for not being sufficiently cooperative with party operations, particularly its probe into a money scandal involving the alleged misuse of her secretaries' salaries.

"The suspension meant that I was not able to work as a lawmaker," Tanaka said. "That prevented me from making efforts to promote lawmaker-proposed laws, which I wanted to do most."

Tanaka admitted that her statements made during a July session of the Lower House Deliberative Council on Political Ethics did little to dispel the suspicions surrounding her.

"I decided to resign from the Diet so as not to further aggravate public trust in politics, which has already been severely damaged by a series of scandals involving politicians," said Tanaka, the daughter of late Prime Minister Kakuei Tanaka.

The by-election for Tanaka's Niigata No. 5 constituency will be held Oct. 27 along with five other by-elections. Tanaka's son, Yuichiro, is likely to run in the election, LDP sources said.

Prime Minister Junichiro Koizumi expressed surprise at Tanaka's abrupt resignation, but he said he respects her decision to leave the Diet.

"For a lawmaker, resignation is the toughest decision," Koizumi said at his official residence. "So I respect her decision."

Koizumi added that Tanaka's resignation is unlikely to have a major impact on the course of his administration.

Tanaka was Koizumi's key ally in his ascent to prime minister in the LDP presidential race in spring 2001.

Former LDP Secretary General Hiromu Nonaka said the Diet should continue in its efforts to clarify the suspicions against Tanaka, even if she is no longer a politician.

"She probably chose to resign as even her former secretary accused her of the allegations," he said.

The resignation "is a result of 'theater democracy,' " he said, referring to the excessive media coverage of politicians, mainly by television stations.

Tanaka's money scandal surfaced in April when some weekly magazines reported that she had pocketed salaries that were meant for her secretaries.

Opinion polls following the July ethics council session showed that many people were unconvinced by her appearance before the council to counter the allegations.

Given these circumstances, Tanaka is unlikely to be able to sustain her once strong showing in popularity polls, according to political analysts.

Tanaka spent nine months as foreign minister beginning in April 2001 but never got anchored in the position despite her high popularity with voters, clashing with ministry bureaucrats over personnel transfers, reform steps and policy issues.

By the summer, Koizumi had also lost faith in Tanaka over personnel matters as she challenged the Cabinet's appointment of a new ambassador to the United States.

On the diplomatic front, she was the source of numerous controversies -- sometimes triggered by information leaked from bureaucrats and her foes in the LDP -- that stalled Diet deliberations.

Already discredited for her diplomatic fortitude, Tanaka became increasingly shunned from the decision-making process, especially after the Sept. 11 terrorist attacks in the United States.

"I cannot believe (the LDP) is trying to block me from carrying out 'diplomacy with a visible face,' " she told reporters after the Diet prevented her from attending a U.N. General Assembly session in November.

One achievement Tanaka can be credited with was her sharp criticism of lawmaker Muneo Suzuki's influence on the Foreign Ministry.

Tanaka's direct confrontation with Suzuki over whether he pressured the ministry to bar two nongovernmental organizations from attending an Afghanistan reconstruction conference in Tokyo in January cost Tanaka her post, as she was sacked so that Diet proceedings would return to normal.

Her attacks on Suzuki over his influence on policy toward Russia and official development assistance eventually led to his arrest over allegations that he accepted bribes.