The Prime Minister's office has confirmed she received correspondence about Andrew Falloon last week.
Jacinda Ardern and Judith Collins. Source: 1 NEWS
The Rangitata MP announced his resignation at the upcoming election today, after National leader Judith Collins said she was "advised of an issue relating to Andrew late on Friday afternoon".
"We have dealt with it this morning," Ms Collins said. "Andrew is suffering from significant mental health issues and his privacy, and that of his family, must be respected."
1 NEWS understands the "issue" was alcohol related and involved his personal life and integrity. It is not a criminal matter.
National got the correspondence from the Prime Minister's Office after 4pm on Friday night and it was the first National had heard of it, 1 NEWS understands.
A spokesperson for the Prime Minister today said an "item of correspondence (was) sent to the PM's office last week".
"With the correspondent's permission, the letter was forwarded to the Leader of the Opposition. We treat all correspondence confidentially."
The PM’s office was sent correspondence about Mr Falloon, ahead of his resignation today. Source: 1 NEWS
"All matters to do with Andrew Falloon's resignation are a matter for the Leader of the Opposition."
The Prime Minister was asked about the correspondence at her post-Cabinet press conference today.
She said she was advised of the “general nature” of it, but was not told the identity of the person who sent the correspondence or which MP it was about.
“My office dealt with it appropriately… Now it sits where it needs to sit, with the National Party,” she said.
Ms Ardern thought there was a 48-hour turnaround from when it was received by the Prime Minister’s office to when it was passed onto National leader Judith Collins.
Mr Falloon is the 13th National MP to announce they won't be standing in September's election, with the decision coming after high-profile MPs Amy Adams and Nikki Kaye said last week they wouldn't stand again.
"As I noted in my maiden speech three years ago, when I was younger I lost three close friends to suicide," Mr Falloon said today.
"It was an extremely difficult period in my life. Unfortunately, recently, another friend took their own life, which has brought back much unresolved grief.
"I have made a number of mistakes and I apologise to those who have been affected."
"Recent events have compounded that situation and reminded me of the need to maintain my own health and wellbeing. I have again been receiving counselling."