Dr Ashley Bloomfield says a woman in her 20s in the family travelled to Rotorua on Saturday while she was symptomatic. [Source: RNZ]

Dr Ashley Bloomfield says a woman in her 20s in the family travelled to Rotorua on Saturday while she was symptomatic.

This as the ministry is working to find out where she went in Rotorua.

Prime Minister Jacinda Ardern and the Director-General of Health are giving a briefing with updates on the new COVID-19 cases and the alert level changes.

The government last night announced that four COVID-19 cases of unknown origin had been found in a family in South Auckland. This prompted a move to alert level 3 for all of Auckland from noon today and level 2 restrictions for the rest of the country.

Restrictions will last until at least midnight on Friday, but experts are warning people to prepare themselves for the possibility they will remain in place longer.

A child who attends Mount Albert Primary School is believed to be involved with the community cases.

People in Rotorua and around the country should seek advice if they have symptoms, Dr Bloomfield says. The woman who was symptomatic was with a child – who later tested positive – and had visited some family and tourist locations during their visit there, he says.

Ardern says the whole country has gone to level 2 because the pair travelled to Rotorua.

There are currently testing sites available in Rotorua (on Vaughn Rd) and Taupo for people in the area, he says.

The family are still in isolation at home and the ministry is working with them about possibly going into quarantine, he says.

No members of the family require hospital care at this stage.

The ministry is testing all close and casual contacts of the family that have come into contact with them recently, which the ministry estimates to be 130 people including workplace colleagues.

Three colleagues of one of the new cases and his partner are symptomatic and are isolating, Dr Bloomfield says.

He says there is a finance company and a Mt Wellington cool store involved with the new cases. However, officials are not ruling out that the virus could be surviving in the refrigerated environment and surfaces of the cool stores, which has four locations across Auckland.

The number of confirmed cases remains four at this point, and “a number” of others have been tested but the results of those is not yet known, he says.

The ministry is using genome sequencing on all those who have tested positive to try and track the source of the virus.

Ardern refuted suggestions doing the rounds that the government knew about the new cases earlier than yesterday, she says Dr Bloomfield was first told by the Counties Manukau DHB chief executive and then he told her.

She first learned of the cases about 4pm yesterday after a public event in Whanganui, she says.

Ardern and Dr Bloomfield will provide another update at 4pm.