In a statement, Collins thanked Kaye and Adams: "Nikki and Amy have both made incredible contributions at very senior levels with consistent dedication to their work and to their constituencies. I wish them the very best for the future."
Earlier today in a statement Adams said she would not accept a ranking on the National Party list.
"Last year I made the decision that I would retire at this election and accordingly I did not seek nomination for the seat of Selwyn that I have held for 12 years. In May I was asked to stay on as a list only candidate and take on the role of co-ordinating our Covid-19 Recovery policy framework," she said in a statement.
"As I said at that time I decided to stay because with the scale of challenges the country was facing, I saw being able to contribute in this way as an honour and a role I could not turn down.
"With Todd Muller's decision to resign the leadership the most important issue for our party was to get a strong and effective leadership team in place without delay and I am proud at the way in which the caucus managed this. I am in no doubt that in Judith Collins we have the right leader for the challenges ahead and Judith and the team have my full support.
"My time as an MP for the National Party and as the MP for Selwyn has been an honour and a privilege and I remain humbled and grateful at the opportunity I've had to serve this country."
Kaye: Step up or step out
Kaye told Newstalk ZB this morning that her breast cancer fight had taught her that life can change in a moment.
"I have always believed you step up or step out," she told Mike Yardley.
"I couldn't predict the events with Todd [Muller].
"Breast cancer has given me a lens on life that is different from other people. Life is very short, " said Kaye, who added she was "OK" health-wise.
She said she felt the "weight of responsibility" quitting so close to the September 19 election, and would fight to help National win.
Nikki Kaye was adamant yesterday she would announce her exit, in spite of efforts to dissuade her. Photo / Mark Mitchell
"People will always find a reason to ask you to stay but I have given twelve years of my life to public service. I have given it everything. I have worked incredibly long hours and I think I'm allowed to choose a decision that's best for me."
Kaye, National's deputy leader for 53 days, described the pressure of leadership as "intense" but said she was "absolutely up for it".
"While it's been a hard period, you have the Hamish Walker situation and obviously the nature of Todd's circumstances - they're difficult but I think I'm absolutely up for that," she said.
Kaye said there were "some extraordinary events that were out of our control" but it was the right thing to step-up to the leadership.
There were more candidates coming through so Kaye said she didn't believe it when people said her departure would leave a hole in the party.
Kaye said she'd recently had a good poll from her Auckland Central electorate which indicated she would retain the seat - but said "you never take anything for granted".
All the best to Nikki Kaye in whatever she decides to set her mind to next. Talking to community across Auckland Central, it’s clear she’s been a hard-working local MP. Nothing can ever be taken for granted in politics, and leaving on one’s own terms is a powerful decision.
"I will do everything possible - I will be on the phones - to try and ensure that Auckland Central is retained by the National Party."
Amy Adams also quitting
The NZ Herald reported exclusively this morning that Kaye was quitting. Adams made her announcement later this morning.
Amy Adams, left, is expected to quit today amid the fallout over Todd Muller and Nikki Kaye's brief leadership.
Collins is due to have a press conference at Parliament this morning to announce her caucus reshuffle. She originally tipped it as a "minor" reshuffle to allocate the portfolios held by herself and new deputy Gerry Brownlee.
But with the dumping of health spokesman Michael Woodhouse and now the departures of Adams and Kaye, the education spokeswoman and a former education minister, the minor revamp has turned into a big exercise.
Newstalk ZB political editor Barry Soper said Amy Adams was also quitting.
Kaye said earlier today in a statement: "While Judith made it clear to me that I would be part of her senior leadership team and education spokesperson, I am ready to retire. I believe Judith is absolutely the right leader for the party at this time and I will be supporting Judith and the party to win this election.
"While I don't think it was possible to predict the events that have occurred, what I have learned from breast cancer and other life events is you can't always predict what is around the corner.
"I have spent most of my adult life serving the public and the National Party. This is personally the right time for me to leave. Cancer has taught me that life can change in a moment and I am ready for the next chapter."
Kaye said she would "never forget the compassion showed to me by the people of New Zealand when I was diagnosed with breast cancer".
The alternative to not leaving now, said Kaye, was putting herself forward and then halfway realising "oh, God this isn't the right thing".
"I think that would have been a worse situation so I had to make my decision pretty quickly given the timing of where we're at. I understand that it will be difficult for people to work through that."
Kaye said it was an "extraordinary privilege" to be an MP.
She had already been selected for her seat of Auckland Central, which she has held since 2008, and will stay on until the September 19 election.
She stood down as deputy when the caucus held an emergency meeting to elect Collins to replace Todd Muller as leader.
Muller resigned suddenly on Tuesday morning under the strain of the job, saying he realised he was not the right person to lead the Opposition and it was affecting his health.
Kaye said she had "huge respect and admiration for Todd, Michelle and their family as they work through this difficult time. I hope that people continue to show compassion for Todd".
She told ZB she still believed Simon Bridges was not the person to lead the party.
In her statement, Kaye said it had been a privilege to serve as MP for Auckland Central for nearly 12 years, and in Cabinet under John Key and Bill English.
"I have been very proud to progress the large investments in school infrastructure, the roll out of fast uncapped school internet connections and progressing digital fluency and second language learning. I am also proud of delivering significant ACC levy cuts and passing legislation ensuring greater transparency of ACC levies, food safety reform, cell alerts for civil defence and recovery legislation.
"As the first National MP to win Auckland Central in our country's history it has been an absolute privilege to serve four terms. I have loved being a local MP progressing projects such as a conservation park for Great Barrier, a number of local school redevelopments, the City Rail Link and apartment law reform.
"I intend to support the party to find a candidate quickly to ensure Auckland Central continues to have a National MP. I want to thank the people of Auckland central, Waiheke and Great Barrier Island for their support over the past 12 years.
"I have always tried to be a strong advocate for freedom and personal liberty during my time in Parliament particularly around conscience issues. I also hope that the work that I have done in areas like education has made a positive difference to young people."
"Nikki and Amy have both made incredible contributions at very senior levels with consistent dedication to their work and to their constituencies.
"They are both highly-skilled professionals who will continue to make a difference in their next careers.
"I thank them for everything they have done for the National Party and New Zealand politics over the years, and I wish them the very best for the future."
Kaye quitting blindsided colleagues
Kaye's announcement has blindsided senior MPs.
"Nikki will make her own announcements when she is ready," said Brownlee, the man who replaced Kaye as deputy leader. "I don't know about that decision just yet. I haven't had it directly reported to me."
When asked about whether Adams would stay on, Brownlee told MediaWorks the new line-up would be announced this morning.
National MP Shane Reti, who was promoted to the health portfolio by Collins yesterday, earlier told Newstalk ZB he was unaware of Kaye's decision. "I'm still to have that confirmed. I know as much as you do."
National MP Mark Mitchell told TVNZ he would be sad to see Kaye go. "She's made an enormous contribution for our country in Cabinet with the education portfolio. And let's not forget she had some health challenges to get over. So of course very sad to see her go but there's life after politics as well."
Kaye, 40, has been at the vanguard of the urban liberal arm of the National caucus, promoting gay marriage and euthanasia, and is an important figure within the party. She stepped down as a minister in the John Key Government to fight breast cancer. Her exit will be a major blow for Collins and the party, who are already losing former deputy PM Paula Bennett and deputy Speaker and former minister Anne Tolley.
It is understood several people had tried to dissuade Kaye from quitting or at least to put more distance between the decision and the events of the past 10 days but she is adamant.
It is understood she was disappointed by Muller's sudden resignation.
She has come in for some criticism over the handling of the Covid patient privacy breach scandal, which led to the imminent resignation of first-term MP Hamish Walker from politics at the election and which appeared to place intolerable strain on Muller.
Walker and Woodhouse both received details of Covid-19 patients from former party president Michelle Boag, who got it in her capacity as acting chief executive of the Auckland Rescue Helicopter Trust. She has resigned from that role and from the party.
Walker forwarded them to media outlets and finally confessed to being the source, which cost him his job.
Woodhouse did not forward it to news media, but confessed to Muller about having received it from Boag four days after first seeing news reports about it. Muller asked Kaye and his No 3 Amy Adams to handle the Woodhouse issue.
Reports emerged last night from National that Woodhouse had wanted to put out a statement on Wednesday saying he also had received the patient material, but that Adams and Kaye had wanted him to wait until later in the week.
In the event, he put out his statement on Friday. Collins replaced him yesterday as health spokesman with Whangārei MP Shane Reti.
Kaye would almost certainly not be quitting politics had Muller remained as leader. In that respect the privacy breach scandal can be linked to four resignations: Walker, Muller, Boag, and Kaye.
Kaye defeated Judith Tizard for the traditional Labour stronghold of Auckland Central in 2008, then twice beat Jacinda Ardern, now the Prime Minister, and held it again in 2017.
Greens list MP Chloe Swarbrick is contesting the seat, as is NZ First list MP Jenny Marcroft and Labour's 2017 candidate, lawyer Helen White, who was 1581 votes behind Kaye.
