Kaye said she had enjoyed a new closeness with her family since finding out she was sick, but telling her mum was "very, very hard".
"It was my mum's birthday so I actually delayed telling her by a day. My family has been amazing but I actually saw my mum's face crumple."
At 36, Kaye said it was a fluke she found the lump in her breast as she had not yet started getting mammograms.
The diagnosis "broke" her life and meant her career as a promising young politician had to be put on hold.
"One moment I was on my way to Wellington, the next minute I was on a table getting poked and prodded and had essentially stepped aside."
Now Kaye is planning her return to parliament, but getting well is her number one priority.
Kaye said the diagnosis was still "raw", but a positive result of finding out she was ill had been a new outlook on life.
"Now I just don't worry about the little things I used to worry about.
'I just think 'frick, I'm alive, it's sunny'. I hope that's a permanent new state of mind."
Harre, who also faced a breast cancer diagnosis in 2011, encouraged women to get checked regularly, a sentiment Kaye echoed.
"I think one of the things I've learnt is that everybody has a different journey and there are lots of different kinds of breast cancer," said Kaye.
"It can be more aggressive in younger women."
She recommended even younger women get a mammogram,and if they felt anything unusual to go to their GP and referred right away.
"Don't muck around," she said.
"In the scheme of things it can be the difference between saving your life and you've just got to go and do it. It takes a couple of minutes."
How to keep an eye on your health when it comes to breast cancer
The Ministry of health offers a range of information about breast cancer as well as links to resources on their website.
Mammograms are free for women between 45 and 69 years old through the country's national breast screening program.
The national screening unit can be called on 0800 270 200.
The New Zealand Breast Cancer Foundation is the country's leading breast cancer education and awareness organisation.
For advice, call the foundation's specialist breast care nurse on 0800BCNurse.