Jami-Lee Ross has admitted he regrets "many things" about last year, but stood by issues he raised about his former boss.
The Botany MP spoke to media on his first day back at Parliament on Tuesday, where he reflected on the past year, and how he thinks the National Party deserves another chance to govern.
But the former National MP stood by his attacks on leader Simon Bridges last year, suggesting that his former boss' low polling reflects the issues he raised about his leadership.
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"The public's now telling the National Party the same things I was seeing in the internal polls last year. It would be interesting to see how well the National Party would do with a popular leader."
In October, Mr Ross accused his then-boss of being a "corrupt politician". He released secret recordings of conversations he had with Mr Bridges, where the pair could be heard discussing what to do with a donation.
Mr Ross alleged Mr Bridges directed him to split up a $100,000 donation from a Chinese businessman into smaller amounts. The National leader was also recorded calling fellow MP Maureen Pugh "f***ing useless".
"Simon Bridges is someone who's been out and met the public, they've got to know him, and now they're giving their verdict on him," Mr Ross said, referring to the latest Newshub-Reid Research poll that puts Mr Bridges below Judith Collins as preferred Prime Minister.
While Mr Ross stood by his claims against Mr Bridges, he said he regrets "many things about last year" and said he wishes he could "go back and do many things over", when asked about his relationship with Sarah Dowie.
Police confirmed an investigation into a text the Invercargill MP allegedly sent to her former colleague Mr Ross, telling him he deserved to die, which he said triggered his mental breakdown in October.
It's understood Ms Dowie had a long-term affair with Mr Ross, which ended in mid-2018.
Mr Ross said police contacted him last week to update him on both the investigation into the text message and the allegations he made against Mr Bridges, however he would not go into detail.
"I'm pleased that the police have the information in front of them and they're working on those issues."
Mr Ross said he returned to Parliament to "advocate on issues that I think are important for New Zealanders and also my constituents".
He said mental health issues and the way in which it's been funded in the past is "important" to him, adding that he's "going to spend time working on that and other issues like housing affordability and transport links in the Botany electorate".
"I've had a lot of good feedback from people out and about in my community," he said.
"I was concerned when I first got out of the mental health institute to see what their reaction would be, but there's a huge amount of compassion and kindness from humans, and I'm enjoying that and appreciate that from my constituents."