A new law is likely to be in place by next year, to detain high-risk sexual or violent offenders past the end of their prison term.
The Government says its Public Protection Orders would apply to a small but extremely dangerous group of up to 12 offenders in the coming decade.
The Public Safety Bill was introduced to Parliament on Tuesday to enact the orders, which are mainly aimed at child sex offenders.
Justice Minister Judith Collins says the High Court will decide which criminals are subject to the order.
Some could be indefinitely required to live on prison grounds.
Ms Collins told Checkpoint the law change is aimed at offenders like multiple rapist Stewart Murray Wilson, who was released three weeks ago, although under strict conditions.
She says the new law would apply to between five and 12 offenders each decade.
Ms Collins says the new law has been designed to be as consistent as possible with the Bill of Rights.
She says the safety of New Zealanders is paramount and should not be jeopardised by those offenders who continue to pose a serious threat once their prison term is up.
"It's not double jeopardy. It's a civil detention regime which can be reviewed every year, so it's not as though it's something that's in place that's there forever, but it can however last until it's no longer needed. So that's the difference really between that and the extended supervision orders."
The Public Protection Orders were promised by the National Party in the run-up to last year's general election.
The law is likely to come into effect sometime in 2013, Ms Colllins says.
