Japan's justice minister, who has been facing calls to quit over past links to an organised crime group, has resigned citing health reasons, a cabinet official says.
Keishu Tanaka, 74, quit on Tuesday a day after he left a Tokyo hospital where he had checked in on Friday with chest pain, irregular heart beat and high blood pressure.
Tanaka's resignation is the second by a minister since Prime Minister Yoshihiko Noda took office in September 2011.
The prime minister has approval ratings of about 20 per cent in polls and is being pushed hard to call elections that analysts say his party could lose.
"The resignation is likely to further weaken Noda's support within his party. Obviously, it will become more difficult for him to exert leadership," said Mikitaka Masuyama, professor at the National Graduate Institute for Policy Studies.
"But it is uncertain whether this could be a trigger for an early election ... Given falling public support for the government, there is no benefit in him dissolving parliament and calling snap election at the moment."
Tanaka's health problems followed days of calls for his resignation after a magazine report linked him to the Yakuza organised crime group.
But Osamu Fujimura, the chief cabinet secretary, told a news conference the justice minister stepped down for health reasons.
Tanaka said he acted as a matchmaker at a mobster's wedding and attended a party hosted by the head of a crime group about 30 years ago.
He explained he was not aware of the groom's mob connections or the nature of the event at the time.
Tanaka has also admitted shortly after his appointment that his party branch accepted $5,300 in donations from a company run by a foreigner between 2006 and 2009. Accepting funds from foreign nationals is illegal if done so knowingly.
Tanaka's office said he had returned all of the money, according to media.
Noda promised in August to hold an election "soon" as part of negotiations with the opposition on a plan to raise sales tax.
The Tanaka scandal is the latest in a string of setbacks for Noda, the ruling Democrats' third prime minister in as many years, who is expected to lose the next election.
In September last year, days after Noda formed his government, Yoshio Hachiro, then trade minister, quit over comments about radiation following a visit to the Fukushima region.
Fukushima is scene of a nuclear plant accident that was triggered by an earthquake and tsunami in March 2011.