Japan has been stung by its third political scandal in a week after the country’s new industry minister - whose predecessor resigned over allegations of misspending - admitted that his staff had spent office money at a sex bar.

The revelations deal another blow to the administration of the prime minister, Shinzo Abe, which was already facing a backlash over its attempt to turn Japan’s nuclear reactors back on and its stalling plans to revive the economy.

As news of the sex-bar scandal broke, industry minister Yoichi Miyazawa, a Harvard graduate and former top bureaucrat in the finance ministry, distanced himself from the affair, saying he wasn’t present at the club in the city of Hiroshima.

But he acknowledged that some staff from his office had billed 18,230 yen ($170) as entertainment expenses during a visit in September 2010, Jiji Press news agency said.

“I came to know of that through a media report, and it was true,” Miyazawa said in Tokyo on Thursday. “It is also true that I myself was not there,” he added.

It was not immediately clear if Miyazawa - a nephew of late prime minister Kiichi Miyazawa and a cousin of foreign minister Fumio Kishida - would step down.

“[Miyazawa] will handle the case properly,” said the chief cabinet secretary, Yohishide Suga, the government’s top spokesman, in the only comment from Abe’s ruling Liberal Democratic party.

On Tuesday, Miyazawa was tapped to replace industry minister Yuko Obuchi, who stepped down over claims she misspent political funds, while the justice minister, Midori Matsushima, also quit after days of allegations that she had misspent money in what opponents insisted was an attempt to buy votes.

The double resignations earlier this week marked the first significant problem for Abe since he came to power in December 2012, ending years of fragile governments that swapped prime ministers on an annual basis.

They were also a blow to Abe’s proclaimed bid to boost the profile of working women in Japan.

The industry ministry oversees the energy sector and is the face for Tokyo’s attempts to convince a sceptical public on the safety of restarting stalled nuclear power plants - more than three years after the Fukushima atomic crisis.

All of Japan’s 48 operational nuclear reactors are switched off. But Tokyo has been pushing to return to a source that once supplied more than one-quarter of Japan’s energy, as heavy energy import bills weigh on the country’s trade balance.