COVID-19: Everything we know about the south Auckland church Delta sub-cluster

There are about 58 cases of COVID-19 linked to the largest sub-cluster in New Zealand's Delta community outbreak - the Assembly of God Church in Auckland's Māngere.

It's worrying some experts, with one labelling it "depressingly familiar" to the Auckland outbreak last August - where Pacific people made up nearly 60 percent of community infections. 

"The susceptibility of Pacific communities to the devastating impacts of infectious diseases is well documented in Aotearoa/New Zealand," said Dr Debbie Ryan, principal researcher for Pacific Perspectives.

"The reports that Pacific people make up more than 50 percent of the cases in this COVID-19 outbreak… are depressingly familiar."

It comes as the Delta variant continues to spread in Auckland, with another 41 new cases reported on Tuesday - bringing the outbreak total to 148.

Modelling shows things could still get worse before they get better, with Prime Minister Jacinda Ardern admitting cases haven't yet peaked.

So how did COVID-19 spread at the Assembly of God Church? Here's what we know.

Of the 148 cases of COVID-19 detected in the community, a large proportion are of Samoan ethnicity - due to 58 people linked to the Assembly of God Church testing positive.

The sub-cluster has been epidemiologically linked to the original Auckland outbreak, Director-General of Health Dr Ashley Bloomfield said on Tuesday.

It's also spread to the capital, with several COVID-19 cases identified in Wellington linked to the church. About 27 church groups, including some from Wellington, had travelled to Auckland for the August 15 service.

Dr Bloomfield couldn't, at this stage, say exactly how many were in attendance.

"On the church cluster, that is a combination of people who were both at the service on August 15 and household and close contacts," he told reporters.

"What I can say is there are well over 500 people tested as part of that cluster and then, of course, in addition to those at the service [it's] getting a handle on their close contacts - particularly the household contacts."   

Work was continuing to identify all those contacts.

"That work is proceeding, at pace, just to get that denominator for that cluster," Dr Bloomfield said.

Anyone who was at the church between 9am and 3pm on August 15 has been told to isolate for two weeks and get tested for COVID-19.