Prosecutors on Tuesday demanded one year behind bars for former senior lawmaker Kanezo Muraoka for his alleged involvement in concealing a 100 million yen political donation by a dentists' group.

Muraoka, 74, has pleaded not guilty. His lawyers are scheduled to make their closing arguments in the Tokyo District Court on Feb. 2.

In seeking the prison sentence, the prosecutors characterized the former chief Cabinet secretary as "lacking in awareness of social norms by continuously keeping campaign funds unpublished in political funding reports" despite his many of years of experience as a lawmaker and holding key Cabinet posts.

Muraoka is charged with conspiring with Toshiyuki Takigawa, former treasurer of a Liberal Democratic Party faction, in March 2002 not to report the 100 million yen donation provided by the Japan Dental Association in July 2001.

Muraoka was at that time acting chairman of the faction, named the Heisei Study Group, which was then led by former Prime Minister Ryutaro Hashimoto.

The prosecution said Muraoka bears heavy responsibility because he laid the blame on Takigawa and denied his own involvement.

Takigawa, 57, has been found guilty of violating the Political Funds Control Law for his role in the case.