Female prisoners could be driven to a nearby court for the night and returned to jail the next morning due to the exploding prison population.
The women's prison in South Auckland is almost bursting, and if the population reaches 462 inmates, the plan to sleep some prisoners in the holding cells at the Manukau District Court will be implemented.
They will be driven eight minutes from the jail to the courthouse for a night in the 2.4m by 4m cells, before being cleared out by 7am when the court needs its facilities back.
The move is worrying Katie Bruce from the Just Speak social justice organisation.
"They are designed for you to sit in for a couple of hours while you are in court - they are not designed for it to be housing," she told 1 NEWS.
Dave Clendon from the Green Party said it was an "extremely poor" way to treat vulnerable New Zealanders.
The prison muster could reach the 462 mark today, but would fluctuate.
Corrections said the use of court cells was a last resort, if there were no other prison beds or police cells available.
Associate Professor of Sociology at the University of Auckland Tracey McIntosh, who has researched incarceration and runs a course at Auckland Women's Prison, said too many women are being held in remand or locked up for low-level offences.
"We have seen this really significant increase in women's incarceration over the last 10 years, in fact out-pacing the men," Dr McIntosh said.
New Zealand's total prison population is more than 10,000.