Babies will be able to stay in jail with their mothers to the age of two under new legislation that has now become law.
Under current law the limit is six months.
The change will be introduced through an Order in Council when the three women's prisons have constructed new facilities for inmate mothers.
Babies will be able to stay in jail with their mothers until they are two-years-old.
Newborn Georgia is starting her life inside where her mother is serving a five year jail term.
"She doesn't know that she's in jail. This is to her like a home," says her mother who does not want to be identified.
"They just sleep and eat laugh at six months old. But at one and two they're running around and you can teach them things, you know you get to watch them for just a little bit longer."
The bill was drafted by Green Party MP Sue Bradford and Parliament's law and order select committee gave it the green light in November last year.
Up until now only low security sentenced women have the option to keep their babies in prison with them. But under the new bill's provisions, women who have been remanded in custody or who have a high security classification will also be entitled to apply to keep their babies with them.
Prison bosses say decisions will be based around the best interests of the child.
Bradford says we were behind the times with the old system.
"This bill's an attempt to try and bring us up to the modern world in regards to how we treat mothers in prison," says Bradford.
The change would bring New Zealand into line with most comparable western jurisdictions.
There will be rules around having babies in jails and applicants will be screened for mental health or substance abuse problems.
An applicant with convictions involving sexual or violent offending will be automatically ruled out.
"They can not have an offence against children, that was sexual or violent and they must also agree they must undertake assessment for their mental health and substance abuse issues," says Bronwyn Donaldson, Corrections Department.
Others are not convinced.
"I would rather see the debate be a little wider - about should we have mothers and children in prison as suppose to should we put more children with their mothers in prison," Lyanne Kerr, New Zealand Federation of Prisoners' Aid and Rehabilitation Societies.
The bill passed its third reading on a voice vote.