New police search and surveillance laws have come into effect overnight.
The Search and Surveillance Act, which was passed through Parliament in March, extends production and examination orders to the police and legalises some forms of surveillance.
It will let more government agencies carry out surveillance operations, allows judges to determine whether journalists can protect their sources, and changes the right to silence.
In March Justice Minister Judith Collins said it brought "order, certainty, clarity and consistency to messy, unclear and outdated search and surveillance laws".
The Act draws together, under one statute, the powers that existed under 69 separate laws.