A fire alarm at an Auckland MIQ facility is not likely to be the source of new positive community case.

Director of Public Health Dr Caroline McElnay said she was aware of reports about a fire alarm going off at the Grand Millennium.

"The fire alarm was 8pm on Monday night. This is not likely to be a source of infection for the case as she was already symptomiatic on that day," she told reporters.

The new case was announced on Thursday and it isn't linked to the border, nor to a managed isolation or quarantine (MIQ) facility.

The infected person is a student at the Auckland University of Technology, lives alone, went on limited outings and hadn't visited a supermarket while infectious. They also worked in a customer-facing role at clothing store A-Z Collection on High St.

As a result of this new community infection, everyone who works in downtown Auckland is asked to work from home on Friday if possible.

"Out of an abundance of caution, we are asking people to work in downtown Auckland to work from home tomorrow," Dr McElnay said.

Minister of COVID Response Chris Hipkins said he will have more information on Friday.

"Tomorrow we will have more information, and we will make further decisions - including possible adjustments to our alert levels."

He said the infection could still be quite contained which is why it doesn't meet the threshold for increasing alert levels yet.

The infected person lives in the Vincent Residency on Vincent St and CCTV footage is being reviewed for safety. Everyone in the apartment building will be in isolation for the next three days.

Hipkins said people should take "enhanced precautions" and "anyone using public transport should be using a mask".