There are now five known community cases and more than 23 exposure events linked to New Zealand's latest Covid-19 outbreak as the nation is plunged into an alert level 4 lockdown. 

Health teams yesterday revealed a 58-year-old Auckland man was the first person to test positive in the latest outbreak, before Prime Minister Jacinda Ardern said this morning there was now a further four cases linked to the man. 

Here is what we know about the cases. 

• Case 1 is a Devonport man, aged 58. He was described as being a type of "tradesperson" by the Prime Minister this morning.

The man wasn't vaccinated and there are now locations of interest connected to him in Auckland and the Coromandel. However, health teams said he was very good at scanning into places he visited using the NZ Covid Tracer app. 

About eight locations the man visited were private residential homes. Another 15 locations of interest listed on the MoH website were public places where members of the public could have possibly visited. 

• Case 2 is an Auckland Hospital nurse and close contact/member of Case 1's household.

She is fully vaccinated and believed to have been asymptomatic. The Auckland District Health Board is now having an internal lockdown as it rushes to prevent a Covid-19 outbreak at Auckland Hospital. 

• Case 3 is a close contact/member of Case 1's household.
• Case 4 is a close contact/member of Case 1's household.
• Case 5 is a work contact of Case 1.

Minister for Covid-19 Response Chris Hipkins said it was possible contact tracers using the NZ Covid Tracer app would find more community cases among people, who weren't showing symptoms of Covid. 

He also expected the number of locations of interest to grow. 

PM Ardern earlier said the fact a fully vaccinated nurse was able to contract the new Delta Covid variant didn't show the vaccine had failed. 

The vaccine has been shown overseas to in the most part prevent serious illness and hospitalisation, she said.