The PM says an Air Force sex attack victim won't be forced to pay Defence legal costs.

Prime Minister Jacinda Ardern has waded into a row over legal costs demanded of Air Force sex attack victim Mariya Taylor.

Ardern said her "personal expectation" was the New Zealand Defence Force would not collect the $138,000 it asked the High Court to award against Taylor - a sum Taylor has said she cannot afford.

Told of the Prime Minister's stand, Taylor broke down in tears on the phone from her home on Australia's Sunshine Coast.

Phil Johnson/Stuff Mariya Taylor cried with relief at hearing the prime minister's stance on the issue of costs.

"I was so worried we'd lose our house, lose everything if we had to pay Defence's costs, so I'm relieved to hear the prime minister say she won't let that happen," Taylor said.

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"This fight has dominated the past four years of my life. To lose my High Court case because it was said to be too late to ask for compensation was devastating, but I have been overwhelmed by the support I've had from friends and family, and particularly from former and current New Zealand servicepeople, in the past few days."

Taylor's money woes are not over yet, however. She also faces a claim of $57,000 from her attacker Robert Roper, a former air force Sergeant, who is in jail serving a 13-year sentence for raping and sexually assaulting his two daughters and others.

Friends have set up a fundraising page to help her with costs.

Ardern said she had been following Stuff's reporting of the Taylor case, and shared the "discomfort" shown by Justice Minister Andrew Little in an interview on Monday.

SUPPLIED Mariya Taylor as a young airwoman, serving at Whenuapai Air Force base.

Little said he was uncomfortable with a large employer such as Defence "chasing after" an employee for costs.

"In most cases where there is this huge power imbalance you wouldn't [expect] the more powerful party to be chasing that person in an unreasonable way," he said.

The prime minister said she was seeking a further briefing, but confirmed that whatever the ruling from Justice Rebecca Edwards in the ongoing case, Mariya Taylor should not have to pay the Crown's portion of legal costs.

JASON DORDAY/Stuff The prime minister talks about a Pike River apology, the Mariya Taylor Air Force sex attack case and what's on the cards for Christmas.

"What I have been advised is that even when a court awards costs, that does not mean they have to be pursued. I'm now setting out my personal expectation that we will not pursue those costs."

Taylor, a former airwoman at Auckland's Whenuapai air base, is suing Roper and the Defence Force for compensation over abuse she suffered at the hands of Roper at the base in the 1980s.

She claims the Air Force knew about Roper's behaviour but failed to keep her safe. A High Court judge has agreed she was ogled, groped and repeatedly locked in a cage by Roper, but found she had left it too late to file a claim.

Taylor has lodged an appeal.