The High Court has told Corrections to think about how it can move illegally transferred prisoners back to Wellington.
Almost 70 women were moved from Arohata Prison to Auckland and Christchurch since September last year, because of staff shortages.
The court ruled in August the move was discriminatory based on gender - because the women's individual circumstances were not taken into account in the same way a male prisoner's circumstances were.
Following a hearing last week, Corrections deputy national commissioner Brigid Kean said one of the units at Arohata would be re-opened for 20 low-security prisoners.
Fifteen low- and medium-security prisoners currently kept at Arohata in high-security conditions and four or five women from other prisons would be held there, under the supervision of four prison guards.
As the first tranche of women were released over the next six months or so, more women from other prisons could be moved back to Arohata, Kean said.
It followed months of back-and-forth about whether Corrections could safely increase the capacity of Arohata Prison based on its current staffing situation.
"At this stage, Corrections has not identified a short-term measure that would involve a significant restoration of sentenced prisoner capacity at Arohata prison," an October affidavit said.
"It expects that it will be in a position to achieve this as corrections officer numbers continue to increase, but that is in part dependent on the number of prisoners in custody, which is not in Corrections' control."
In a decision released on Friday, Justice Francis Cooke said tight resources were not a good enough reason to break the law.
He told Corrections to make a list of women sentenced since August last year who were still at other prisons, and reconsider their placement. It must take into account each women's individual circumstances, Corrections' own Women's Strategy, and the interests of any children.
Staffing at Arohata must also be looked at, in light of the earlier court ruling, he said.
"The chief executive has said that Arohata can now be partially re-opened, albeit operating less extensively than it was before the challenged decisions. That step does not appear to eliminate the unlawfulness identified in the judgment, however," the judge said.
"There will still be women who have been transferred out who will not be returned to Arohata when they should be, and the proposal is only to operate the Te Araroa wing for short term imprisonment, at least in the first instance.
"Resource constraints are not a legitimate reason for failing to comply with the law. But equally the court's role is not to take over the chief executive's decisionmaking functions, or to provide ongoing supervision.
"The appropriate orders are to require the chief executive to reconsider both sets of decisions ... so that the unlawfulness identified by the court no longer exists."
The judge did not set a deadline for the decisions to be made, but said they "should not be deferred".
A lawyer for some of the transferred women, Victoria Casey, said the court's ruling that the women's children must be considered was a "major victory".
"It is also a clear direction to Corrections that its lack of staff is not an excuse for breaking the law," Casey said.
"If women need to be returned to Arohata to be near their children, then Corrections simply has to find the staff and resourcing to make that happen."
Co-counsel Amanda Hill said the decision specified Corrections must reconsider Arohata staffing - but only after fresh decisions about who was eligible to return had been made.
"This means that the future of Arohata will be determined by the women who need to be there, rather than the staff Corrections decides to retain there," Hill said.
"The decision not only gives women the chance to return to Arohata, it also confirms that they can go on to seek compensation from Corrections for the discrimination they have experienced ... the longer Corrections takes to fix this, the bigger the possible financial burden will be."
However, until Corrections made the required changes, the discrimination against women in prison would continue, Hill said.
RNZ
