Jacinda Ardern says she'll be keeping a "close eye" on possible price gouging of face masks.
The prime minister addressed concerns about price hikes today after 13 more cases of community transmission were confirmed in Auckland.
The city was placed into Alert Level 3 at midday yesterday, with the rest of the country moving to Level 2, after a new outbreak of Covid-19 was confirmed Tuesday.
The Government is encouraging people, particularly those in Auckland, to wear masks if they leave their homes.
Ms Ardern face masks had been added to PriceWatch.
"We are asking people report in if you're seeing any of that, we are keeping a very close eye on it," she said.
"We're asking people not to try and capitalise on the situation New Zealand is in.
"I would be very surprised if that was happening in some of our supermarkets because some of them are getting their supply from Government. We released two million masks into Countdown."
Ms Ardern added that people don't necessarily have to have a surgical face mask.
"A face covering that you perhaps fashion yourself is adequate.
"We are actually looking through the advice of health to distribute some information of the kind of face coverings, if you're using your own, are going to do the job, just so that people don't have to rely on purchasing something that might be financially out of their reach."