When parliament's Lower House ethics committee convenes later this week, five senior Liberal Democratic Party officials are expected to testify on what they knew about a political slush fund scandal, and where the money went.

It would be only the 10th time that the committee has been convened since its formal establishment in 1985.

On Tuesday, the Upper House ethics committee met for the first time ever. All eyes are now on who among 32 Upper House LDP members caught up in the scandal will agree to testify.