New Zealand First's president says he resigned citing a refusal to sign off financial reports on moral grounds.
Lester Gray has confirmed reports his resignation letter to the party said he was unwilling to sign the party's 2019 financial documents because he was given a lack of information about donations and expenses.
Sources within the party who have seen the letter confirmed it raised the concerns.
Gray announced he was stepping down and leaving the party under mysterious circumstances on Wednesday, after less than a year on the job, and after two weeks of medical leave.
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He has confirmed reports he refused to sign the party's 2019 financial reports with the information he had been provided.
"As president, the limited exposure I have had to party donations and expenditure leaves me in a vulnerable position," the letter reads, according to Stuff.
"This type of operation does not align with my moral and business practice values, and I am therefore not able to support the party any longer."
Gray refused to comment further on the matter but confirmed the report.
"I'm just trying to slip out of the party quietly and get on with my life," he said.
He earlier announced on social media he was resigning from the role of president and leaving the party, but did not give a reason for his departure.
"I will always treasure the wonderful people I have met and the friendships we have started," he said.
Comment has been requested from the office of NZ First leader Winston Peters, currently travelling overseas, and a number of other party members.
The resignation comes two weeks ahead of the party's annual conference.
Clutha Southland New Zealand First board member Jude Patterson – the wife of NZ First MP Mark Patterson – has been appointed acting president until a replacement is elected at the conference. Two party members have put their hands up for the job.
Patterson earlier described the departure as a shock but said she could not comment on further on the matter.
"We can't discuss our members' health issues. We have to respect Mr Gray's privacy," she said.
A New Zealand First spokesperson said: "NZF respects the decision Mr Gray has made, thanks him for his valuable contribution, and wishes him well for the future."