Chief Cabinet Secretary Takeo Kawamura repeated Friday that he has used his political funds legally and said his office is preparing to disclose receipts that back up his suspiciously high expenditures.

"My support groups had been active in accordance with the Political Funds Control Law, but they must be managed so as not to raise doubt," Kawamura said during a regular news conference. "I am a bit bewildered at the media reports."

Three of his political support groups have been under fire for reporting ¥22 million in expenditures — including almost ¥15 million in office expenses — between 2005 and 2007, while using a rent-free office.

The apartment office in Chiyoda Ward, Tokyo, had been owned by the late Tatsuo Tanaka, a lawmaker of the ruling Liberal Democratic Party. Kawamura officially inherited Tanaka's political district in Yamaguchi Prefecture.

"The apartment, the office, had been used by Tanaka as a home base for his political activities in Tokyo and I inherited it," Kawamura said. "I took over everything from Tanaka — from his political will to his political organizations."

The apartment had been loaned out for free to Kawamura's groups by the late Tanaka's son, but Kawamura said his support groups had paid part of the utility expenses.

The government's top spokesperson, however, admitted that he should have reported the office under the donation section of his annual political funds report.

Kawamura, however, disclosed that the apartment in question was not the home of his former public secretary. The secretary, who also worked under the late Tanaka, has lived in Kanagawa Prefecture for about 20 years, Kawamura said, adding that she would sometimes sleep over in the apartment in Chiyoda Ward, Tokyo, after working late or in preparation for work early in the morning.

The three support groups disbanded this March and unified into Kawamura's political funds management body.