The Search and Surveillance Bill passed its third and final reading in Parliament today.
Justice Minister Judith Collins said the new Search and Surveillance Act 2012 brought "order, certainty, clarity and consistency to messy, unclear and outdated search and surveillance laws".
"I am pleased to have finally reached this point with this significant legislation. The Search and Surveillance Act 2012 is a comprehensive reform of search and surveillance powers, and complements the Government's initiatives on organised and drug crime."
The Act draws together, under one statute, the powers that existed under 69 separate laws. It extends production and examination orders to the police and legalises some forms of surveillance, such as video surveillance.
A decision of the Supreme Court last year held that police video surveillance in certain circumstances was unlawful. A temporary law legalising such surveillance will expire this April 17.
Ms Collins said some provisions in the Act would come into force by 18 April so that the expiry of the Video Camera Surveillance (Temporary Measures) Act 2011 does not endanger ongoing investigations using covert video surveillance.