Police evidence from hidden cameras in 47 cases - involving 229 accused - are in jeopardy until Parliament can fix the law, Police Minister Judith Collins says.

The Video Camera Surveillance Bill passed its first reading under urgency last night. The Greens, Maori and Mana parties and Chris Carter opposed it.

It will be considered by the justice and electoral select committee and reported to Parliament on Monday.

The bill would legalise police covert video surveillance on private property with a search warrant, a practice the Supreme Court said was illegal.


But use of hidden cameras would still be subject to a person's right against unreasonable search.

The Government has framed the issue over 50 police operations where covert cameras have been switched off since the court decision, and 40 trials that were relying on evidence obtained from hidden police cameras.

Ms Collins released further information during the bill's first reading, including the 229 people accused in cases where evidence was now compromised.

"Over the last year there have been on average 47 camera installations a month ... Some will not fall foul of the law, but others will," Ms Collins said.

"It can be expected a number of operations will not be initiated because of the Supreme Court judgment ... Police do not believe they can continue to use surveillance equipment in the way they have for at least the last 15 years."

Covert surveillance not only fought crime, but increased safety for police informants and others caught up in criminal acts, such as "children in a meth-cook area".

Opponents of the bill, including the Green, Maori and Labour parties, rounded on the Government.

But Act MP Rodney Hide landed the hardest punches, using the view of Chief Justice Dame Sian Elias, who said police had deliberately and knowingly acted unlawfully.


"If we are to have law and order, the critical bit is for the police to operate within the law," Mr Hide said.

"What sort of banana republic is it when the Government of the day comes along and says, 'we don't like that decision of the courts. Let's change the law retrospectively, because we don't agree with the implications with that decision'."