The Democratic Party of Japan on Friday refused to accept a list of 41 nominees for key government positions, maintaining its opposition to the one tapped to head the Fair Trade Commission because his name was leaked to the media, even though when the DPJ was recently in power, it backed him.

The move by the largest opposition party further complicates the nomination process, as the nominees must receive approval from both Diet chambers.

DPJ board members walked out of meetings in both chambers to protest the recent revelation by the media that Kazuyuki Sugimoto was tipped by the Liberal Democratic Party-led government to head the FTC chief, just as deputy chief Cabinet secretaries were submitting the list of nominees.

“I would have reacted differently if the government had submitted a list of nominees separately from the (FTC) nominee,” Shu Watanabe, a DPJ Lower House member, told reporters after he left the meeting.

Before the Dec. 16 general election, when the DPJ was the ruling party, it picked Sugimoto, a former vice finance minister and chairman of Mizuho Research Institute, to lead the FTC.

Azuma Koshiishi, who heads the DPJ’s Upper House caucus, said Thursday the rule still stands that any potential candidate whose name is reported by the media in advance must be disqualified. Sugimoto’s planned nomination was reported by the Yomiuri Shimbun.

The so-called Nishioka rule was agreed upon between late DPJ lawmaker Takeo Nishioka and Takashi Sasagawa of the LDP when the names of 28 nominees were leaked back in 2007. The rule led to a 20-day hiatus in the process of appointing the Bank of Japan governor in 2008, before incumbent Masaaki Shirakawa was approved.

The LDP and its ally, New Komeito, have considered changing the rule, but the DPJ has been trying to block such a move.

“The DPJ rejection does not make sense. . . . They asked us to accept the nominee when they were in power,” LDP deputy Diet affairs chief Tsutomu Sato said.

The DPJ’s tough stance is casting a dark shadow over the nomination of other key positions the Diet must approve, including the Bank of Japan governor, who is planning an early exit, and deputy governors, whose terms expire March 19.

The ruling bloc lacks a majority in the Upper House and needs 16 more votes to get its way. If the DPJ, which has 87 seats in the chamber, does not give in, the LDP needs to seek other cooperation.