Toshikatsu Matsuoka, 62, was found in his apartment on monday unconscious and rushed to a hospital, where he was declared dead hours later, a Tokyo Metropolitan Police official said.

"We've just confirmed that he is dead," said the spokesman, who spoke on condition of anonymity because of department policy.

Matsuoka had faced heavy criticism over a scandal involving suspicious book-keeping practices in his offices, and was scheduled to appear before a parliamentary committee this afternoon for further questioning.

Government officials confirmed Matsuoka was hospitalised on Monday, but Chief Cabinet Secretary Yasuhisa Shiozaki refused to confirm widespread reports the minister hanged himself from a door in his apartment.

The reports of suicide were a blow to the government of Prime Minister Shinzo Abe, which has been buffeted by scandal and has seen a recent plunge in support ratings.

Support for Abe's Cabinet fell to 32 per cent, down 11 percentage points from a similar poll in April, a survey by the national newspaper Mainichi, taken over the weekend, showed on Monday.

The government's disapproval rating rose to 44 per cent, up from 33 per cent, the Mainichi said.

A separate poll by the Nikkei business daily showed Abe's popularity falling to 41 per cent, down 12 percentage points from the previous month. - DDNews India