A new mother found out she has just weeks to live, as she sat at the hospital bedside of her baby girl who will need open heart surgery to survive.

Five weeks after giving birth to Brooklyn, who was born premature and with a heart defect, Diana Sevealii, 36, was diagnosed with cervical cancer and is urging women to have regular smear tests.

She has refused chemotherapy as she wants to spend as much quality time as she can with her daughter, now seven weeks old, who is in Auckland's Starship Hospital.

"It breaks my heart knowing I am leaving her," Sevealii told the Herald on Sunday.

"I have only just got her."

Sevealii is from Cannons Creek in Porirua but is living at Auckland's Ronald McDonald house, accommodation for families with children at the hospital.

This week Brooklyn had a three-hour operation to unblock a valve in her heart to allow blood to be pumped into her lungs.

She will also need open heart surgery before she is 2 years old to survive because of a defect called Tetralogy of Fallot.

"She is beautiful and loving and feisty - she gets that from me. She's come a long way and she still has a bit to go - but she's definitely a fighter," said Sevealii.

Brooklyn's condition is life-threatening, said Dr Kirsten Finucane, head of Paediatric Cardiac and Surgical unit at Starship.

"Children can have spells and seizures, their oxygen levels go down. It's a combination of a hole in the heart in the two main chambers of the heart and a blockage in the flow of blood from the right ventricle into the lungs."

Sevealii first became concerned for her own health while eight weeks pregnant after bleeding and clotting, but an initial smear test came back giving her the all-clear.

A further test in the month leading up to Brooklyn's birth showed abnormalities and two weeks ago, while she was with her daughter at Starship, she was given the devastating news that she had terminal cancer.

"They've given me weeks basically.

"I know it's every three years [you should get a smear test] but if you are in my situation have them more often and get a second opinion if you are not sure.

"It's probably not a thing Pacific Island women would put on their list of priorities but it's important. It can save your life."

She doesn't blame anyone for what's happened but is frustrated at the all-clear she had received after the initial smear test.

"I have to face it the best way I can for Brooklyn and my family - and that is to live life."

Sevealii has back pain and is short of breath but is opting for healthy juices and alternative medication to manage.

She is praying for a miracle and makes the most of the ordinary moments.

"I want to give Brooklyn as many cuddles as I can and change all her pooey nappies as I can – this is family time."

Before her illness, Sevealii worked as a receptionist at Maddison recruitment.

It upsets Sevealii, who is not in a relationship with Brookyln's father, that she might not see her daughter get married and have children.

"I am going to miss all of that but I will be there in spirit to protect her, guide her and watch over her."

Her family are working out who will look after Brooklyn.

Sevealii's older sister, Moira Peet, has returned from New York where she lives and has promised her sister she will "love and guide Brooklyn" when she can no longer.

"It's unfortunate we have to gather in such challenging circumstances," Peet said.

"I love Di to bits she's always been a second mum to my kids and all our nephews and nieces. Wherever she goes she is known as 'Aunty Di'."

Sevealii thanked Heart Kids - a charity that supports children like Brooklyn - for the support they had shown towards her and her family.

"Annie from Heart Kids has been a huge blessing for me, my family and Brooklyn. She has helped with food and clothing. This week she found a bigger house which is a lot warmer with a lot more bedrooms."

A spokesperson from Heart Kids said: "We will give Brooklyn ongoing support throughout her life".

Sevealii wanted her daughter to "enjoy life , love people regardless of their faults and be the best person she can be".

"And to know her mother loved her so much and would give anything to see her grow up. And she's going to be loved by so many people when I am gone".

A Givealittle page has been set up to help the Sevealii family. To donate, or learn more, visit: https://givealittle.co.nz/cause/di-and-brooklyn.