Police will patrol supermarkets and step up their presence at public places if necessary as tighter Covid-19 restrictions come into place, says Police Commissioner Mike Bush.

Mike told Morning Report police would become more visible in public places.

"There will be powers of course, we don't want to use our authority in this.

"But people need to listen to the advice they're given, listen to the rules that are being laid down."

"It's all about saving people's lives."

The Covid-19 alert remains at Level 2, where events are cancelled, public gathering numbers limited and non-essential travel stopped.

At the next level, public venues and non-essential businesses would to close, and at the highest on the scale, Alert Level 4, everyone would need to be isolated from each other. Essential services would continue but everyone would be asked to stay at home.

Mike says police will ensure there is compliance over public gatherings, which at present are banned for more than 100 people indoors and for more than 500 people outdoors.

"If people are seeing others obviously flout this I want them to get in touch with us."

He asks people to phone 105 - or 111 if they thought it was "really urgent".

"We will respond, we will intervene. People need to comply to the directions that are being given.

"This is unprecedented in New Zealand, so we have to change our policing approach.

"This is our top priority in order to keep New Zealanders safe and keep the country sustainable."

Police are planning how to patrol more visibly and more frequently - if necessary at supermarkets, or wherever people were in public, says Mike.

"We want to make sure that people aren't just complying but they're taking care of each other, and that people are behaving responsibly and that people are being respectful to each other."

A range of legislation including the Health Act, civil defence and emergency laws and the Summary Offences Act will be used.

"We have to work within the law."

Mike says it has been difficult to get all the personal protection equipment police needed, but the police health and safety team have worked hard to make sure they have the required gear.

New guidelines issued for the hospitality sector on Saturday say people going to bars, restaurants and casinos will be expected to stay at least 1m away from each other, and venues have to do head counts to make sure there are no more than 100 people indoors.

-RNZ