Prime Minister Shigeru Ishiba said Friday that holding hearings of a parliamentary political ethics panel in a way that is open to the media is "one method" of allaying public suspicions about a slush funds scandal involving his ruling Liberal Democratic Party.

"So long as there are doubts and concerns, making (hearings) public is one method of dispelling them," Ishiba said, referring to how LDP members embroiled in the scandal should face the panel in the Upper House.

The prime minister made the remark on the first day of full-fledged deliberations over the government's fiscal 2024 supplementary budget bill in the Upper House Budget Committee.

Of the 27 scandal-hit Upper House lawmakers willing to face ethics panel hearings, 23 have sought for the sessions to be held behind closed doors.

"We can urge (the lawmakers to open up the sessions), but it cannot be forced," Ishiba said. "It's ultimately a personal decision."

Ishiba expressed reluctance over a proposal by opposition parties to ban corporate and group donations, saying, "I wouldn't go so far as to say that it violates (Article 21 of the Constitution, which guarantees the freedom of expression), but the relationship must be discussed."

At a meeting Tuesday of the budget committee in the Lower House, Ishiba had said that the proposed ban could violate Article 21.