House of Councilors lawmakers from the ruling Liberal Democratic Party who were involved in a slush funds scandal have begun to express their wish to explain themselves at a parliamentary ethics panel.

The development comes as LDP members in the upper chamber of the parliament believe facing the Deliberative Council on Political Ethics may become a prerequisite for receiving the party's endorsement in next summer's Upper House election.

However, some have expressed concern that attending panel hearings could "open a Pandora's box," as there are unexplained accusations unique to the Upper House side over the scandal, in which some revenues from fundraising party ticket sales were kicked back to lawmakers.