In a rare unanimous vote, Parliament last night strongly backed a bill allowing mothers in prison to keep their babies with them until they turn 2.
Green MP Sue Bradford's bill now goes to a select committee for public submissions.
At present mothers can sometimes keep their babies with themin prison self-care units until they reach 6 months.
Last night Sue Bradford told the House that was far too young for a baby to be removed from its mother.
"Forcible separation at 6 months is nothing short of barbaric. If a baby is ripped away, the despair and trauma can be devastating."
At present there are 13 pregnant women in New Zealand's prisons.
The Corrections Department refuses to disclose precisely how many babies are with their mothers behind bars, but says that at any one time between two and five infants are housed in prison.
Prime Minister Helen Clark yesterday told Radio New Zealand several issues had to be resolved.
"Are you going to wrench a 2-year-old away from the mother if the mother's on a life sentence for murder? Is that going to be in the interests of the child? I think there's those sorts of issues. Are we going to end up having to put childcare centres into our prisons?"
Ms Bradford says the present law denies mothers the right to breastfeed up to the age of 2, as recommended by the World Health Organisation.
Most other countries allow babies to stay in prison for longer.
In Australia the time ranges from one to six years, in Malaysia and Canada it is three years, and in Ireland it's 18 months.
National MP Katherine Rich has argued the change is likely to help rehabilitate mothers and lessen recidivism rates. Maternal separation at an early age could also cause long-term difficulties.
The bill also aims to enshrine the right of mothers to breastfeed their babies.
