Coronavirus: Why contact tracing is so important in NZ's fight against COVID-19

Effective contact tracing is an integral part of New Zealand's fight against COVID-19. 

As the number of cases across the country grows, finding every close contact is more important than ever. 

There are 48 new confirmed cases and 41 probable cases of COVID-19 in New Zealand, the additional 89 cases bringing the country's total to 1039.

The latest figures were announced by the Ministry of Health's Director-General of Health Dr Ashley Bloomfield during the daily press conference on Sunday.

As of Sunday, 156 people have recovered from the virus and 15 are hospitalised, including three patients in the ICU. Two are in a critical condition.

But new modelling by economist Rodney Jones shows that we should be feeling grateful, despite the new cases. 

The research shows the transmission rate overseas is one case infecting four people but here, because of the strict lockdown, our rate is just 2.6.

And our rate is expected to continue falling because everything was shut down so fast. 

While most businesses have been forced to wind down the National Close Contact Centre is busier than ever. 

For the 1039 confirmed or probable cases, the centre has identified more than 5000 close contacts. 

Director of Public Health Dr Caroline McElnay said one of the challenges is how difficult it can be for people to remember everywhere they have been. 

"It can be quite difficult for people to remember exactly what they were doing because they are going back in time." 

The centre is making more than 2000 calls a day and has helped identify the 12 clusters across the country. 

Today there were two new clusters - one in Christchurch and the other in Auckland. 

Dr McElnay said the clusters often revolve around an event which can mean there are hundreds of contacts to work through. 

"What we've seen with some of the clusters or outbreaks that we've got, people have been at an event in the past, and in that situation there can be hundreds of contacts."

The cluster at Marist College in Auckland remains the largest at 66 cases and more than 800 people are considered close contacts for that group.