New Zealand's latest Covid case in the community could be a lot worse, according to one of our top epidemiologists.

A 56-year-old woman, who lives south of Whangārei, was released from MIQ in Auckland on January 13, developed mild symptoms on January 15 and got tested on January 22 after her condition deteriorated.

She is currently in isolation with her husband, who has also tested negative. 

Epidemiologist Professor Michael Baker told Mike Hosking the new case was a learning process for everyone and illustrated how everyone could do better.

As for what more could be done, Baker said looking at how she got infected, he said it was likely she got infected in the MIQ facility and what advice was she given in MIQ before she left.

Baker said the woman did all the right things afterwards but more could be done for the week once she left.

The genome testing, looking at CCTV, testing other staff and people in that facility. asked if it's too loose, Baker said it was a balance and needed to go more to the biosecurity side and was more they could do.

Baker said the case could have been a lot worse and that it was a border case was good news, and the fact she didn't appear to have a lot of close contacts and the outbreak would hopefully be controlled rapidly.

The risk had now gone up several notches. His colleagues believed NEw Zealand needed to look more at the source countries because once they were there was more risk of an outbreak.

He realised the Government needed to balance everything but they needed to move quickly.

"We have to up our defences accordingly and there are things we can do."

Hipkins said it was still too early to say whether any restrictions or alert level changes would be needed, or how the woman got the virus.

"We don't have the relevant information we need to make any further decisions on that. As soon as we do we will keep people informed."

He said anybody who had symptoms should get a test, wherever they were in New Zealand.