Kiwis are being asked to have a supply of masks if New Zealand goes back to COVID-19 alert level 2, Health Minister Chris Hipkins has announced.

Hipkins said on Thursday the Ministry of Health has updated its advice on the use of masks by the public as part of the Government's ongoing response to COVID-19.

"We've seen elsewhere masks can play a role in helping to reduce the spread of COVID-19 when worn by the public where there are cases of community transmission," he said. "I want to restate here, there are currently no cases of community transmission in New Zealand."

He said the World Health Organisation (WHO) is now suggesting that people should be prepared for the use of masks before the need to use them arises.

"The Ministry of Health is now recommending that as part of our collective preparations for any future outbreak of COVID-19, households add sufficient masks for everybody normally resident in their household, to their emergency supply kits," Hipkins said.

"Just as we are prepared by having food and water set aside in the event of a natural disaster, we are encouraging New Zealanders to have a supply of masks set aside at home in the event of a further COVID-19 outbreak."

He said these do not need to be medical-grade masks. They could be reusable or the single-use masks that people see online or in shops.

• NZ could end up like Melbourne, experts warn
• Passengers on cruise ship hit by COVID-19 test positive
• More contagious strain of COVID-19 could be behind Vietnam outbreak
• Justin Trudeau's Kiwi pilot misses birth of first child while stuck in Covid-19 isolation in NZ

"Masks will be most useful when COVID-19 is present in the community and people are mingling in close proximity to each other, like at work or in social situations."

Should we wear masks now?

The country is currently at alert level 1 and Hipkins said at this level it is not necessary for the public to wear masks because there is no evidence of community transmission in New Zealand.

If the country moves to alert level 2, Kiwis will be encouraged to wear masks in situations where physical distancing is not possible, such as on public transport or in shops.

"If there are further outbreaks of COVID-19, masks will be another important component in our strategy for containing the spread of the virus so that we can - if at all possible - avoid further lockdowns," Hipkins said.

"This is of course in addition to strict physical distancing, hand hygiene and most importantly avoiding contact with others if you have COVID-19-related symptoms - all things we encourage New Zealanders to do today."

Hipkins said this is about general preparedness and not a cause for alarm.

"We're asking members of the public to view face masks as they view pieces of their emergency supply kits - important tools that we can all use if we need to use them in the future."

Director-General of Health Ashley Bloomfield said masks have been added to the "toolbox" of measures to combat the virus, should New Zealand need to go back down the alert levels.

"We know COVID-19 is spread from close contact with a person who already has the infection and masks are one tool in the toolbox to help reduce the risk of spread between people, should COVID-19 be in the community," he said.

"Our overall elimination strategy is still based on strong border protection, testing, contact tracing, isolating people who are infected, and of course physical distancing.

"What we are doing is adding masks to our overall toolbox as part of our ambition to avoid having to go up alert levels, should they be required."