Patrons of an Auckland pub have been asked to self-isolate and get swabbed for Covid-19,  after being exposed to someone infectious with the virus.

A person who visited The Malt pub in Greenhithe last Friday between 7.30pm and 10pm, later tested positive.

The infected patron is one of two community cases announced yesterday, among 25 new cases across New Zealand.

Otago University infectious disease expert David Murdoch told Mike Hosking it's crucial people who are at risk of exposure self-isolate, and he hopes they will.

Murdoch says we can't brush this aside as no big deal.

"We need to expect to see cases ... and that we have a system that can respond to it."

Health Minister Chris Hipkins says officials are working "very fast" to make sure any community spread is contained.

LISTEN ABOVE