Jacinda Ardern vows law change after successful push for surrogate baby Paige's dead mother to be recorded on birth certificate

The Prime Minister has promised to make major changes to our surrogacy and adoption laws, Newshub can exclusively reveal.

It comes as Parliament just passed a law unlike any other for one little girl, Paige Harris - the only child ever to have their mother's name as 'not recorded' on their birth certificate.

Paige was front and centre in Parliament on Wednesday - a really big deal, even if she doesn't know it.

Her birth certificate has her mother's name down as 'not recorded'. But Paige's biological mum was Kat Harris, whose egg was used in an IVF surrogate birth.

Tragically, Kat died of unforeseen health complications just before Paige was born - and under the law could not be recorded on the certificate.

Her dad, Kyle Harris, says justice has now been done.

"Happiness is perhaps the overwhelming emotion, relief - it has been a long time coming," he said.

Prime Minister Jacinda Ardern says the law change "helps a father and a husband fulfil a dying wish to his wife - and what is more important than that?"

Paige was being babysat on Wednesday by Renee Johnson, the surrogate mother, who carried and gave birth to her; and Renee's husband Josh, who led the fight to have the name recorded.

Louisa Wall took it to the House.

"This legacy is for Paige, but Paige is providing a legacy for other children - and I think that is amazing," she told Parliament.

The legacy - this promise to change the law for others.

"We need to change our surrogacy laws, and this example proves why. But they are complex pieces [of legislation], we want to get it right so you don't have another situation like Paige's family has shown us," Ardern said.

The Prime Minister is wanting it done this term: "I would certainly hope so."

Paige will now get her birth certificate with her mum's name on it. It will be ready for collection as soon as the Governor-General signs off the law, just in time for her birthday - she turns two years old at the end of this month.

A law just so a little girl can have her identity - and much bigger change on the way.