Finance Minister Taro Aso on Thursday urged the top ministry bureaucrat to behave himself after a report emerged he has sexually harassed female reporters.

"I told him to act with a sense of tension, considering the situation the ministry is in," Aso said during a parliamentary session after the report on Junichi Fukuda.

Aso was referring to public criticism of the ministry over a heavily discounted state land sale to a school operator with ties to Prime Minister Shinzo Abe's wife, and the ensuing doctoring of documents on the deal.

(Finance Ministry top bureaucrat Junichi Fukuda)

The Shukan Shincho weekly magazine reported in its edition which went on sale the same day that Fukuda, administrative vice finance minister, made sexual advances toward a number of female reporters covering the ministry.

The magazine hinted at the existence of an audio source allegedly recording Fukuda's remarks made to the reporters.

However, Aso said he does not plan to investigate the matter or reprimand Fukuda, saying the top bureaucrat has told him he could not confirm the report's content because details such as the dates when the alleged sexual harassment occurred, and the names of the reporters involved, are not specified.

"I will be careful so as not to invite misunderstanding," Fukuda was quoted as telling Aso.

Lawmakers from both the ruling coalition and opposition parties expressed anger toward Fukuda following the report.

"It's unbelievable and extremely regrettable," said Yoshihisa Inoue, secretary general of Komeito, the junior coalition partner of the Liberal Democratic Party headed by Abe. He called on the ministry and the government to take the issue seriously.

Party of Hope Diet affairs chief Kenta Izumi called the report, if true, "outrageous," saying Fukuda should be replaced immediately.