National Party MP Paula Bennett will bow out of politics at the election and venture into the "business world".

Her decision follows last month's leadership change in the National Party after Todd Muller and Nikki Kaye rolled Simon Bridges and Bennett. Bennett was also removed as the party's campaign chair and replaced by Gerry Brownlee.

She informed Muller of her decision at 9am today. She told media this morning he had thanked her for what she had done for the party and that she would be missed.

Bennett summed up her rise in politics, from "a 17-year-old solo mum who dropped out of school ended up being Deputy Prime Minister of this country".

She said that making the call to quit was not "tough at all", and it was time to put herself first. Life was too short for regrets.

"I have had an incredible time in politics for the past 15 years and now I am looking forward to my next career."

She had been reflecting on what she wanted to do in the past weeks. She was "open to opportunities" in the business world and did not have anything specific lined up at this stage.

She will remain a National Party member.

She joked that she would like to stay married so she didn't plan to spend more time with her family.

She looked forward to more fishing.

Former Prime Minister John Key had told her to sort her golf swing, and she would look to do that, but she was most excited about business opportunities.

She had no plans for a tell-all book at this stage, she said.

Bennett said the past two and a half years in Opposition is where she has "probably learnt the most".

"The whole thing though has been a hell of a ride and I have loved it. Now it is time for the next chapter. I am excited to take the skills I have out of Parliament and into the business world. I have always wanted another career after politics and now is the right time for me to go and pursue that."

She said she "had many people to thank".

"I believe that much of my success has been due to the incredible people who have worked with and for me.

"I am particularly proud of my work as Minister for Social Development and Child Youth and Family for more than six years.

"Many think being a Minister is a hands off role. I loved being hands on. I implemented those reforms, drove the change and the daily execution, and most importantly saw people's lives and livelihoods improve."

Asked about welfare changes, she said: "There is an expectation that a lifetime on welfare is an option for people, and almost feels encouraged when it should be a back-stop that is there if you need it."

Moved down the list

It is understood Muller made it clear to Bennett he wanted her to leave after the leadership change, but Bennett stared him down and was given the 13th ranking with the portfolios of Women and drug reform.

Soon after that, Bennett found herself in the position of having to defend Muller as he faced flak for the lack of Māori on his front bench – Bennett was the highest-ranked.

Bennett said just after the leadership change that she had been "hit pretty hard" but it was a part of a politics and she wanted to stay on as an MP.

This morning, Bennett said she wouldn't have stayed if she had been higher on the party list, she said.

She said she never wanted to the leader, and she was more about people and strategy and organising skills. "Those skills were best suited to a deputy role."

"You make you're own luck, but I've been surrounded by the most talented people ... I've had John Key as a mentor and Bill English who backed me and Simon [Bridges] who trusted me... How can I not be filled with proud and gratitude for the people and the party?"

Asked whether the caucus included the type of life experiences that she had had, such as being a sole parent as a 17-year-old, she said "don't judge by the cover" and digging deeper into the caucus would reveal a broad cross-section of society.

She said there were "a few points" that will swing the 2020 election, and National could certainly achieve that.

She will step down immediately from her front bench spot and her shadow portfolios. She wished Muller the best.

Another of Bridges' supporters – Anne Tolley – announced she was leaving last week.

A high-profile career

Bennett is one of National's most high profile MPs, serving as Deputy Prime Minister to Sir Bill English and then as deputy leader to Bridges.

She was on former leader Sir John Key's front bench and in his kitchen cabinet in his last term in power.

She was highly regarded by Key, and said he had not only opened the door for her but wedged it open for her.

She was also one of National's more flamboyant and colourful MPs – renowned for her love of leopard skin suits and high heels. She was not the stereotypical National Party MP – her own background was a solo mum on a benefit.

Her line telling Jacinda Ardern in 2012 to "zip it, sweetie" earned her the top honours in Massey University's 2012 Quote of the Year competition.

Bennett came into Parliament as a list MP in the 2005 election and became the Minister of Social Development in 2008, when she first won the Waitakere seat.

She oversaw an overhaul of the benefit system but was criticised for changing the eligibility requirements for single parent benefits, which she had used herself as a solo mum.

Bennett was also investigated by the Privacy Commissioner after she released the income details of two solo mothers who publicly criticised cuts to a training allowance.

She apologised for the personal cost the whole episode had caused one of the mothers, but disagreed with the finding that she had breached the woman's privacy.

Bennett held several ministerial portfolios including State Services, Women, Tourism, Police, and Climate Change.

She had stomach-stapling surgery in 2017 and later said she had lost 50 kgs within a year.

"I had weight loss surgery for health reasons," she said at the time.

"I have arthritis and the best way to alleviate some of my constant pain was to reduce my weight. I have constantly said I liked the way I looked before - and even adorned the cover of the odd magazine when I was heavier. This size isn't 'better' in my opinion, it's just healthier and different."

She, Tolley, and public service chief executives were unsuccessfully pursued in legal action by NZ First leader Winston Peters, who claimed that details of his superannuation payments were leaked to media to embarrass him and cause him harm.

Bennett said it was wrong for the information to be leaked to the media, but she had no idea who was behind it.

Bennett is the MP for Upper Harbour but was not contesting the seat this year having decided to stand on the list instead.

"Paula lives in West Auckland with her husband, cat and various children and grandchildren all of which seem to come and go as they please," says her profile on the National Party website.

"Since becoming a Celebrant, she has added wedding officiation to her range of hobbies, which include fishing, cooking, music, and a cold chardonnay."