The official New Zealand Parliament page on social media site X has posted a message in memory of Kaye.

"Today, we acknowledge the passing of former MP Hon Nikki Kaye. A member of New Zealand Parliament from 2008 – 2020," it wrote.

An image showed Kaye in Parliament surrounded by her colleagues.

Todd McClay says it is a very sad day.

Kaye was an MP who gave 100 percent all of the time.

He says it's not surprising to see people from across Parliament reaching out with their memories of Kaye.

"There will be a lot of people who will be sad today."

Speaking in Hamilton, Prime Minister Christopher Luxon says Kaye was "true to herself" and lived her life knowing what she wanted to do.

 She was as enthusiastic about her life after politics as she was during politics.

Kaye went to Parliament wanting to represent her community, Luxon said.

The party feels the loss really strongly and a lot of Caucus will also, he said.

Former Prime Minister Sir John Key has paid tribute to Nikki Kaye, saying she did everything “at full noise” and was a force to reckoned with.

“Nikki was an incredible young woman who brought tenacity, determination and dedication to everything she did. Everything was undertaken at full noise and that’s what made her so successful and lovable.”

Key said he had heard Kaye was very unwell and called her about three weeks ago, when they spoke for about an hour and a half.

“I managed to have a really good talk to her. She was honestly in a great space. She described herself as quite a spiritual person so she felt very much at peace with where things were at.

“The thing with Nikki is that she is one of those people, it’s the life you get out of the years, not the years you get out of life. And we’ve lost her so early, but she packed an awful lot into those years.”

Key had become Prime Minister in 2008 – the same year Kaye first entered Parliament by winning the Auckland Central electorate, which until then had long been held by Labour.

He said her win in that seat showed she had “something special”.

“I think those wins in Auckland Central were much more a vote for Nikki than they were for my Government.”

Kay appointed her a minister in 2013, saying now that he had known she would give her all to any portfolio she had.

“I think that she brought to Cabinet a different way of thinking sometimes, because she was a younger person partly but also she mirrored my view that she was economically conservative but socially liberal.”

Key recalled when she had told him she had cancer in 2016: “She initially wanted to leave because she didn’t want to be a burden on us.” 

He said he had understood the diagnosis was more serious than was known publicly at that point, and told her if she had a family and children he would have urged her to leave.

“But I said to her, your life is politics and helping people and you need to fight this thing and come back. So she agreed to doing that and I think it gave her something to focus on.”

Education Minister Erica Stanford says she is heartbroken at the death of her mentor and friend Nikki Kaye.

"My mentor. My friend. Everything I learned when I came to politics was from you.

"Your passion, your drive and your fierce intellect was an inspiration to us all."

She said Kaye  looked after the "newbies" in the National caucus, giving them time and sharing her wisdom.

She described Kaye as "the most incredibly fun person to be around".

"We are all absolutely heartbroken.

"Rest in peace my dear, beautiful friend."

Friend and colleague Maggie Barry told the Herald: "I was shocked when her family told me the sad news."

Barry said: "It’s hard to believe that such a strong determined person has left us.

"Nikki and I worked together on many projects in Parliament (such as in the photo of us at Glenfern I posted on my Facebook page ) when we helped secure Glenfern's future in 2015.

"Nikki was a staunch member of the BlueGreens and an ardent conservationist who actively supported PredatorFree 2050.

"She achieved an incredible legacy in her 44 years and will be remembered for a life dedicated to public service, particularly in her beloved electorate of Auckland Central.

"We will miss her."

"New Zealand has been robbed of such an outstanding and wonderful person far too young. Nikki was probably one of the most passionate, intense and dedicated people I’ve ever met,” he told the Herald.

"Right until the end, she was incredibly positive about her life, the things she had achieved. Very much a peace with what was happening. She described herself as quite a spiritual person. 

"She felt very comfortable with the way life had worked out. Obviously, like anyone she would have wanted a lot more time.at the time when she publicly said she had breast cancer, she was privately saying to me it was much more significant and had morphed into other parts of her body and so the diagnosis initially was pretty dire. 

"When she had her 40th we went along and I think she got up and said they gave her quite a low probability of actually getting to 40," he added.