Government will pass temporary legislation suspending the effect of a Supreme Court decision which ruled covert camera surveillance by police unlawful.
The bill will pass next week under urgency, Prime Minister John Key said.
A permanent fix would be included as part of the search and surveillance bill due to pass after the election.
Mr Key said speed was essential because the ruling in the Ureweras case would have jeopardised police investigations.
He said the Crown Law Office advised Cabinet it meant almost all use of covert video surveillance was unlawful.
"This has significant implications for law and order in New Zealand."
It could impact on up to 40 current trials underway and 50 poilice operations, including some serious criminal offending.
The law change would not affect the outcome of the Ureweras case.
The change would apply retrospectively so prior convictions in trials in which covert surveillance was used to collect evidence could not be overturned.
Mr Key said the government was talking to other parties to secure support for the measure.
He hoped it would have broad support.
"If we can't get the numbers that would mean there would be some serious criminals who would not be brought to justice."
The legislation would clarify that it was Parliament's intent for camera surveillance to be permissible.
- NZ Herald staff