New Zealand's former National MP Andrew Falloon poses for a photo in front of Parliament in Wellington, New Zealand, on Dec 8, 2019. (PHOTO / AP)

WELLINGTON - A lawmaker from New Zealand’s main opposition party resigned on Tuesday after being accused of sending a sexually explicit image to a young woman.

It was the latest in a series of resignations and scandals at the National Party, which faces the challenge of trying to unseat the centre-left Labour coalition led by popular leader Jacinda Ardern in the September general election.

The lawmaker, Andrew Falloon, said in a statement on Monday that he will not be contesting in the September polls, and apologised for a “number of mistakes” without giving details. He said he had been dealing with some mental issues following the suicide of a friend.

I am absolutely appalled by what I have been hearing this morning. 

Judith Collins, Leader of the New Zealand National Party

ALSO READ: New Zealand's opposition picks Collins to face Ardern in vote

But Falloon quit parliament immediately on Tuesday after it was revealed in the media that he had sent an unsolicited and indecent image to a 19-year-old woman.

“I am absolutely appalled by what I have been hearing this morning,” National’s newly elected leader Judith Collins said.

The matter came to light after a university student made a complaint to Ardern’s office last week, who passed it on to Collins, the Prime Minister’s office said.

Falloon was not immediately available for comment and the National Party declined give details of his whereabouts.

Collins was handed reins of the National party just last week amid a series of scandals and an exodus of senior leaders, which threaten to damage National’s chances at the polls.

Earlier this month, National Party member Hamish Walker resigned after admitting to leaking names of coronavirus patients to the media.

READ MORE: NZ's Ardern loses key aide as election looms amid pandemic battle

Shortly after, former National Party Chief Todd Muller quit just over 50 days into the job, saying it was affecting his health. Just two days later Muller’s deputy Nikki Kaye and senior leader Amy Adams also said they will not contest in the elections.

Opinion polls last month showed Ardern’s Labour Party would be able to govern alone with 50 percent support while National only had 38 percent.