Coronavirus: Mystery surrounds COVID-19 cluster of 25 people at Auckland workplace

An Auckland COVID-19 cluster comprised of dozens of positive coronavirus cases is shrouded in mystery, with the Prime Minister and the Director-General of Health both refusing to provide further details.

Government officials are staying mum on the cluster, which they've revealed involves 25 people and originated in an Auckland workplace, but won't say any more about.

When asked about the cluster in his daily coronavirus briefing at the Beehive on Thursday, Dr Ashley Bloomfield said privacy issues are stopping him speaking more freely.

"We will provide details about, for example, a school or an event where it is pertinent," he told media.

"But in some instances, we will withhold the location and name of the workplace if we think it's going to create privacy issues - that's the only reason."

According to the Ministry of Health, a cluster is a group of COVID-19 cases linked together by a common location. Most clusters have a link to someone who has travelled overseas.

When asked why the Government wouldn't say anything else on the cluster when so many people had been affected, Jacinda Ardern was adamant that those who needed to know already did.

"People who are affected will get a phone call from the Ministry of Health - so if they're affected, they know," she said.

There are many COVID-19 clusters in New Zealand. The three largest are linked to a Matamata bar (64), a Bluff wedding (87) and Auckland's Marist College (84).

The number of new coronavirus cases has started to dip over the last few days. Thursday's total of 29 cases was the lowest daily total since March 23, when the alert level 4 lockdown came into effect.