A Democratic Party of Japan executive surprised the administration Thursday when he said his party, the largest opposition force, will reject the government’s planned nominee to lead the Fair Trade Commission because his name was leaked in a media report.

Azuma Koshiishi, who heads the DPJ’s Upper House caucus, said the Diet still has a rule where a government nominee for certain key posts will be rejected if their name is reported in the media in advance.

“It is . . . a problem when (the parties) are trying to map out rules on nominations that need Diet approval,” Koshiishi said.

The tough stance may signal the DPJ will complicate the nomination process for the Bank of Japan governor as well.

The morning edition of the daily Yomiuri Shimbun reported that Kazuyuki Sugimoto, a former vice finance minister and chairman of Mizuho Research Institute, would be nominated in the Diet on Friday to head the FTC.

“I was really surprised (by Koshiishi’s comment), so now we are preparing to propose (a candidate) as early as possible,” Chief Cabinet Secretary Yoshihide Suga said.

The Liberal Democratic Party-New Komeito ruling bloc lacks a majority in the Upper House, so it needs cooperation from opposition parties to fill certain posts, including the FTC chairman as well as the BOJ governor and vice governors.

Whether the administration can persuade the DPJ to accept its nominee to lead the central bank has been considered a test case for how the LDP can handle the divided Diet.

The FTC helm has been vacant since September, when the DPJ-led government failed to appoint a successor to Kazuhiko Takeshima amid fighting between the ruling and opposition parties.