Veteran National MP Nick Smith apologised for voting against gay marriage, and cited his work in conservation as a career highlight, in his valedictory speech in Parliament.
After 31 years, he is the longest serving MP in Parliament.
Dr Smith said his first ministerial job was in conservation.
"Conservation is the best job in the Cabinet room. To get it once is lucky; twice is to be truly blessed," he said.
Smith said his appointment came in the wake of the Cave Creek disaster when a Department of Conservation viewing platform collapsed into a ravine near Punakaiki on the West Coast in 1995.
"My job was to put the systems in place with Director-General Hugh Logan to ensure DOC's thousands of structures and facilities would be safe. We also established in '99 the Conservation Rangers Programme that has trained over 600 since, to do the skilled DOC fieldwork professionally and safely."
Smith said other career highlights included advocating for the Kahurangi National Park, working to protect the Lords River on Stewart Island in 1998 and then initiating the process for establishing the Rakiura National Park in 1999.
He thanked the dedicated public servants who helped him in his work.
"My favourite are those hardy DOC field staff out in the wet and cold in the most rugged corners of New Zealand, repairing tracks, killing pests, and protecting nests," he said.
"Conserving a good chunk of our land mass for nature was the challenge of last century. The focus needs to shift seaward," Smith said.
Smith said as minister of conservation in the '90s, making the Poor Knights a marine reserve was controversial.
He said he needed a police escort because he had received a death threat.
"I was confronted only a few years ago at Whangārei Airport by a cheeky local who introduced himself rather unnervingly as the guy who had made the threat. He jokingly told me not to worry as he now thought it was such a great idea that he would shoot anybody that would dare undo the reserve."
Smith said although he had subsequently been involved in creating 17 marine reserves around New Zealand, he was disappointed that the government was yet to make progress on a Kermadec Ocean Sanctuary.
"The commercial fishing there is negligible. The history of customary fishing is minimal. This is about New Zealand - Māori and Pākehā, stepping up and doing our bit globally to better care for the world's oceans," Smith said.
He said the "most satisfying chapter" of his career was being part of the English / Key government.
"We shared a vision of where we wanted to take New Zealand and we had built the strong relationships and policies in Opposition to work as a team. My work involved creating the Environment Protection Authority and a fast-track but robust consenting process. This enabled us to get on and build projects like Waterview in Auckland, Transmission Gully in Wellington and Christchurch's Southern Motorway."
Apology to LGBT+ community
Smith apologised for voting against gay marriage in 2013.
"The error is all the more personal with my 20-year-old son being gay. I wish to put on record today my apology to New Zealand's LGBT+ community.
"I pay tribute to Louisa Wall, Fran Wilde and Amy Adams for their leadership that has improved the lives of my son and thousands of other New Zealanders. I also acknowledge Jenny Shipley's courage as the first PM to attend a Gay Pride parade in '99," Smith said.
As well as acknowledging his family, Smith acknowledged the Speaker, past and present National leaders, parliamentary colleagues, family and friends in the gallery.
"I also want to acknowledge the many good MPs who post election 2020 did not have this opportunity," he said.
Smith to remain party member but with no 'active involvement' in National caucus
Smith abruptly resigned last week, citing the loss of the Nelson seat and a Parliamentary Service inquiry into a "verbal altercation" in his Wellington office.
He had been warned details of a Parliamentary Service investigation into the row between him and a staffer had been leaked to the media and a story was about to break.
But no such story came - and it is still not clear why he was told one would be coming.
Smith refused to answer questions about the leak when asked by RNZ.
"I'm just not interested in that conversation. Today I'm just reflecting on my 31 years as a Parliamentarian."
Smith said he will not be having any "active involvement" in the National caucus but will remain a member of the party.
"I have got absolute confidence that there are the talented people in that caucus to make sure those National Party values that were founded all the way back in 1936 are part of the next government of New Zealand."
He was asked if National leader Judith Collins will be the next prime minister.
"I'm just not going to get into a debate about the broader political issues. I have confidence in Judith Collins and I wish her and the rest of the team well."
Smith is set to re-join his family's crane and construction business and said he is looking forward to life as a private citizen.
After being booted from Parliament at the election, Harete Hipango will take Nick Smith's place in the National caucus.
