apan's Finance Minister Shoichi Nakagawa has said he will resign for health reasons, amid claims that he was drunk at a recent G7 meeting.
Mr Nakagawa said he would resign after the government's budget is passed by the lower house of parliament.
He earlier apologised for his behaviour at last weekend's news conference in Rome but blamed cold remedies for a slurred performance there.
He said he had not drunk more than a sip of alcohol before facing the media.
"I want to apologise once again as I caused tremendous bother to people because of the press conference after the G7 in Rome," Mr Nakagawa told reporters in Tokyo on Tuesday.
"I visited hospital last night and this morning and was diagnosed to have a bad lower back, cold and fatigue. I'll do my best to fulfil my duties for the remaining days."
Mr Nakagawa's resignation is seen as a major blow to Prime Minister Taro Aso's government in an election year, correspondents say.
The news conference in Rome followed a meeting of finance ministers focussing on the current world economic crisis.
Footage showed Mr Nakagawa slurring his speech and closing his eyes repeatedly as if he was dozing off.
At one point, he mistook a question aimed at the governor of the Bank of Japan as one intended for him.
"It's embarrassing," said Democratic Party Secretary General Yukio Hatoyama. "This has sent a message to the whole world. He's damaged the national interest."
He explained that he had sipped wine at a luncheon toast on the day of the news conference, but had not consumed an entire glass.
He said he had taken too much medicine, including cold remedy, and that had made him drowsy.
Mr Nakagawa has denied reports - including the view of a former prime minister - that he is a regular drinker.