She said she fled with her child because she could not get support in Australia, because she is a New Zealand citizen.
While the Court of Appeal did not reveal the reasons for ruling in her favour, the case will have wide implications for future Hague Convention cases in New Zealand.
The president of the Court of Appeal, Justice Kós, ruled on the case with Justice Goddard and Justice Brown.
They had signalled before the March 6 hearing they would be reviewing the current precedent for Hague Convention cases in New Zealand.
The Hague Convention was designed to send a child back to their country of habitual residence, where a child custody case can then be heard.
Originally, it was created with the idea that mothers could enact the Convention when fathers kidnapped children and left the country.
But in the years since it was created, the majority of global cases have involved a mother fleeing domestic violence, and the father then ordering them back to his country of residence.
A clause in the Hague Convention states that if a child would be at grave risk of being thrust into an intolerable situation by returning, a court can deny the order.
But the clause does not take into account violence against a mother, and the impact that may have on a child.
Ben Keith and Daniel Vincent were the lawyers working for the mother, and Keith said during the case that if the mother was at risk of serious harm, so too was the child.
"We did say when we sought leave that we were not seeking to revisit the Family Court judges finding in relation to the child," Keith said in court last month.
"What we do say is that the child's circumstances include at least the mother's trauma."
Court sought more information from applicant father
During the case the three judges asked several questions about the conditions the mother would be thrust into if she were forced to return to Australia.
They asked about the financial support that would be available to her in Australia, where she might live in the immediate and longer term, and what social supports would be on offer in the absence of family or friends.
The lawyer for the father, John Gwilliam, said there was support for the mother in Australia.
"We know that there are social agencies who can step in the breach immediately, in terms of social housing and so forth," Gwilliam said.
Justice Goddard replied, saying: "But does that show that the situation will be tolerable, or that there will be some Band-Aids on an intolerable situation to prevent it from being catastrophic, rather than intolerable?"
And when talking about social issues, Justice Goddard said it was obvious there would not be much support, and Justice Kós agreed.
"You can't really go out on a bowling night with a state agency," Justice Kós said.
"It's not the sort of thing they do."
The court also put more onus on the applicant parent by asking for the criminal records and charges previously laid against him, and court documents to back up claims he had made in the High Court.
Generally, once a parent had requested the return of their child, the onus of proof lay with the fleeing parent.
Many mothers RNZ has talked to said that given the situation they found themselves in, they did not collect the level of evidence needed to prove their case.
And obtaining police reports and the like from overseas was extremely difficult, if not impossible, for some women.
The father in this case failed to provide the requested information by the March 6 hearing.
The court ordered the information to be delivered in the following three weeks.
By requiring the applicant father to provide that information, other courts will likely use the same powers in future cases.
The full reasoning for the Court of Appeal decision is expected in the next eight weeks.
