An urgent law change to allow police to film secretly on private property could be slowed up by Labour, which says it will not support the legislation unless it goes through proper process.
Prime Minister John Key yesterday announced plans to pass "patch" legislation to authorise police use of covert video surveillance.
The measure would suspend the effect of a Supreme Court decision last week that ruled police surveillance on Maori land in the Ureweras was unlawfully obtained.
Crown Law had advised Cabinet it meant almost all use of covert video surveillance was unlawful, and could affect up to 40 trials already underway and 50 police operations.
Mr Key said it was essential to move quickly, and the bill would be passed under urgency next week as long as other parties supported it.