Checkpoints around Auckland have been set up overnight to stop non-essential travel out of the city.
On Sunday, Prime Minister Jacinda Ardern announced Auckland would return to alert level 3 for three days following the discovery of three new COVID-19 community cases. The rest of the country would be at level 2 as a precaution.
The alert level changes came into effect at 11:59pm on Sunday and at midnight, the police re-established roadblocks around the Auckland region.
A spokesperson for police said the boundaries would mainly be in the same places as they were set up during Auckland's lockdown in August 2020.
"Eight checkpoints on the outskirts of Auckland will be stopping vehicles and questioning drivers, ensuring there is no non-essential movement through the region," the spokesperson said.
"From midnight, anyone attempting to travel across the regional boundaries should expect to be stopped and asked for proof of essential travel."
Police Commissioner Andrew Coster said police will be quick to respond to the change, having managed at alert level 3 before.
"We will continue work with a graduated response, starting with education. We are once again asking the public to be safe and abide by the alert level restrictions for their region.
"In Auckland, we will continue to be visible and provide assurance to the community, and to checkpoints around the region's Super City boundaries."
He also noted that the 105 non-emergency police line has been experiencing high demand. Meanwhile, the Ministry of Health and MBIE have developed an online registration system to support requests for exemptions to leave and come into Auckland for business, service and personal reasons.
"During this time, travel between alert level areas will be strictly limited," the Government COVID-19 website says. "Anyone wanting to travel between alert level 3 and alert level 2 regions needs to check whether they are eligible to travel between different areas of the country."