SINGAPORE — New Zealand's justice minister has resigned with immediate effect, after failing an alcohol breath test in the wake of a car crash.

Kiri Allan, 39, was charged with careless driving and resisting arrest.

She is the fourth minister from Prime Minister Chris Hipkins' cabinet to leave since March, ahead of elections due in October.

No casualties were reported from the crash, which took place in the capital Wellington on Sunday night.

Following her arrest, the former minister was detained at a police station for four hours before being released. She is due to appear in court at a later date.

Ms Allan, whom Hipkins said had been suffering from "extreme emotional distress", will remain as a member of parliament for now.

"She understood that retaining her ministerial warrant was untenable, especially for a justice minister to be charged with criminal offending," said the prime minister in a press conference.

Ms Allan, who was also minister for regional development, conservation, and emergency management, had recently taken time off due to "personal difficulties", only returning to work last Monday.

She confirmed her separation from her partner last month and is also facing accusations of poor working relationships with staffers.

In a statement on Monday, Ms Allan said that she had returned to parliament believing she could juggle personal challenges with her job.

"My actions yesterday show I wasn't okay," she said, adding that she will consider her future in politics.

Ms Allan was once seen as the darling of the Labour party. She was even tipped to succeed former prime minister Jacinda Arden, who stepped down from her role earlier this year before Mr Hipkins took over.

Her resignation is the latest development in what Hipkins admitted has been a "messy" time in his own party.

Transport and immigration minister Michael Wood resigned in June over his failure to disclose a possible conflict of interest in stock ownership. A month earlier, customs minister Meka Whaitiri switched sides to join another party.

Four months ago, police minister Stuart Nash in March was also fired after it was revealed he had given confidential information to donors.

An April opinion poll predicted a close contest in the upcoming election between the centre-left Labour party and its main opposition the National party. — BBC