Former Diet member Joji Yamamoto, under arrest on suspicion of misusing more than 20 million yen in state salary payments for a woman falsely registered as his secretary, has told investigators he did not use the money for personal expenses, according to his lawyers.

Yamamoto, 37, who has admitted most of the allegations against him, told prosecutors he used the salary payments to cover office expenses, the lawyers said.

The former member of the Democratic Party of Japan intends to return the money to state coffers, they said.

Yamamoto allegedly kept some 23.6 million yen in salary payments made between January 1997 and September 1999 for a woman he registered as his full-time government-paid secretary in charge of policy affairs in November 1996, one month after his first election to the House of Representatives.

Prosecutors allege the woman only worked occasionally for him and that he paid her only 50,000 yen to 100,000 yen a month.

Yamamoto resigned from the Lower House last Friday.