The government and police have been granted sweeping powers to enforce alert level 2 under a bill passed under urgency tonight, just hours before the restrictions kick in.
The legislation passed its final reading in Parliament tonight with National and ACT voting against.
The government said the new law would allow authorities to police the Covid-19 restrictions despite the lifting of a state of emergency.
Among other things, the law allows police to enter a person's home without a warrant to shut down large gatherings.
The Act will automatically expire in 90 days unless Parliament agrees to extend it.