Amy Adams has confirmed she is standing for the National Party leadership.

Adams, as Simon Bridges did earlier today, started by paying tribute to former leader Bill English, saying she had begged him to stay.

"We know we need to choose a leader to take us into 2020."

Adams was supported by MPs Nikki Kaye, Chris Bishop, Tim Macindoe and Maggie Barry at her announcement.

She said her ambition was to take National to victory in 2020 with a united caucus.

Her reasons for standing are because she loves this country and it matters to her that it is a country that her children want to grow up in.

"I believe I am the best person for the job," Adams said.

She can reflect a range of values including compassion and integrity, and a proven ability to get things done.

She said National didn't just need a vision, but also a plan to follow through.

"I'll make sure New Zealanders know we care about them."

She said her MPs alongside here were not an indication of potential deputy leaders, but were there because they wanted to show support for her.

She said she grew up with a solo mother, married a farmer and had two children, and has spent 16 years as a lawyer so she could represent urban and rural people.

She also had held 10 portfolios as a minister and hoped she had demonstrated intellectual rigour.

She said she would have to have a stronger public profile if she was the leader.

She was born and raised in Auckland, had worked in the commercial field and chaired the local school board of trustees.

She said yesterday was the first day she had any discussions about the leadership, as she had wanted English to stay on.

She said strong economic growth and strong fiscal management was at the heart of the party, leading to creating opportunities for New Zealanders.

"It's not for me to play out what caucus has decided in that regard here."

She said she had "very strong support", and it meant a lot to her to have Kaye, Bishop, Macindoe and Barry at her side in support for her leadership bid.

She said talk about the deputy leader was speculation and that Paula Bennett was doing a great job.

She said unity was important and National had no intention of following the in-fighting that plagued Labour over its nine years in Opposition.

Adams said climate change was a critical issue and New Zealand had to play its part, but it shouldn't move too quickly to be economically crippling.

She said when she was Environment Minister, she felt that cleaner, better water could be achieved along with a strong farming sector.

Adams did not say whether she had the numbers and would spend the next two weeks talking to caucus colleagues. She also had a lot of respect for Judith Collins and Simon Bridges.

But her unique blend of urban and rural experience, as well as family and commercial experience, made her the best candidate.

"I can be pretty tough when I need to be."

But the focus was on winning the 2020 election. "Our focus is not going to be on the petty skirmishes along the way."

She described herself as economically conservative and socially liberal, and supported gay marriage and euthanasia. But economically, she was in favour of personal responsibility. Adams said she wanted diversity in the party.

Asked about generational change, she said she came into Parliament in the same year as Simon Bridges and Jacinda Ardern, and change was more about a fresh perspective and keeping up with the mood of the public.

She hasn't done any deals with colleagues, and her bid was about the best person to win in 2020.

Asked about Collins' experience in Opposition, which she has not experienced, she said: "We want to be the next Government, not the Opposition."

"I wouldn't be standing if I didn't think I had the skills for the job."

Asked about a consensus vote being more harmonious, she said the caucus was "56 stroppy A-type personalities". "It doesn't worry me at all if it comes to a vote. We'll see how the next two weeks plays out."

She said she was "aspirational" when asked for one word that summed her up.

She said Ardern had a large job ahead of her with lofty ambitions, but she has not revealed much detail. She wanted to focus on policy and delivery, and the Government's cracks along the three governing party lines would become wider as time went on.

Simon Bridges and Judith Collins also declared their candidacy today.

Steven Joyce and Mark Mitchell have said they are sounding out colleagues and considering standing.

Paula Bennett has said she is not interested in the leadership, but would like to remain deputy leader.

Nikki Kaye has ruled herself out of running for either leader or deputy leader.

Jonathan Coleman, who has put his hand up before for the leadership, said this morning he was not ruling anything in or out at this stage.