Former National Party leader Todd Muller has revealed he was blindsided by the toll the role took on his mental health.
Muller secured the position of leader of the Opposition on May 22 after rolling predecessor Simon Bridges.
He along with deputy Nikki Kaye took the reins in an attempt to steer National back on track for New Zealand's 2020 Election in September.
But after just 53 days in the role, Muller unexpectedly resigned on July 14.
He said the told had taken a heavy toll on him personally and "this has become untenable from a health perspective".
"It has become clear to me that I am not the best person to be leader of the Opposition and leader of the New Zealand National Party at this critical time for New Zealand."
On Saturday Muller opened up about his mental health journey with NZME, revealing "anxiety arrived very early on".
"I had anxiety. I had experienced that quite severely and I had panic attacks," he said.
"I need time still to work through that and recover completely but it was really tough for me and really tough for Michelle and the family."
Muller said his business career with Zespri and Fonterra was really stressful but "it was nothing like the personal challenges that I had over the last few months".
"For me, it was very acute. It was very hard."
He revealed there was no "no single moment" when he decided to leave the role, instead it was an accumulation of his 53 days as leader, NZME reported.
"It was more like a drop, drop, drop, drop, that virtually fills the bucket which overflows as opposed to a single boot to the bucket."
In the week after his resignation, Muller surrounded himself with the things that mattered; "love and family and friends, resting, walking and just breathing".
"I think that's what is hard, you were doing the dream job you wanted to do but it was more of 'I'm not enjoying this as much as I thought I would'," his wife Michelle told NZME.
But Muller said: "there's nothing I would change in terms of putting myself forward."
