Prime Minister John Key said an agreement with the ACT party had been reached, filling a gap in the law regarding punishment of New Zealand's most serious repeat offenders.
"I'm taking about those people who consistently pose a very real threat to the safety and security of other New Zealanders," he said.
"Some people will say this bill is harsh, but it's only harsh on the very worst and most dangerous and repeat offenders."
The policy will be incorporated into the Sentencing and Parole Reform Bill, currently being considered by the law and order select committee.
The public can submit views before it's due back in Parliament at the end of March.
If passed into law, someone committing a major violent or sexual offence would receive a standard sentence and warning for the first offence, and a jail term (in most cases) with no parole and a further warning for a second offence.
On conviction for a third offence, the person would receive the maximum penalty in prison for that offence with no parole.
The policy is different than ACT's proposal to have a life sentence with a minimum period of imprisonment of 25 years without parole, but leader Rodney Hide was leased with the agreement, saying it sent a clear message that repeat violent offences would not be tolerated.
"It's a great day for ordinary Kiwis who finally have a government prepared to crack down on violent offending," he said.
"Most offenders won't want to risk a second strike. The result will be a safer New Zealand."
The court can still decide not to order the maximum sentence be served without parole if found unjust. The policy would only apply to offenders aged 18 years and over. It is not retrospective.
The policy would apply to 36 major violent and sexual offences with a maximum penalty of seven years or more.
Labour party leader Phil Goff said the policy of National and ACT was just a gimmick that would make no difference.
"What John Key promised me in the 2008 election campaign is that is would bring in a three-strike policy that would see 572 additional serious offenders locked up by 2011. That figure is now been reduced to 12, 56 extra after five years, so that represents a huge backdown.
"If the policy was effective in keeping New Zealanders safe why would you settle for 56? It's practically going to make no difference at all to community safety," he said.
The three-stike policy announcement comes as UK MPs recommend the opposite. A report, "Cutting Crime: The Case For Reinvestment", states a third of the prison population should get community sentences to stop them from reoffending.
Kim Workman, of Rethinking Crime and Punishment, said the report should be read by every New Zealand MP.
He said the proposed "three strikes" legislation was counterproductive and effectively transferred discretion from the judiciary to the police.
