The good news about two more significant clusters of Covid-19 in New Zealand being officially classed as closed has been offset by a jump in new cases.

Expert epidemiologist Professor Michael Baker said he and other colleagues were calling for improved data to be presented by the Ministry of Health.

Six new cases were reported yesterday after a stretch of low numbers of new cases having been reported by the Ministry of Health this week.

There was only one new case on Monday, two on Tuesday and Wednesday, three on Thursday and Friday, and then the jump to six on Saturday.

Baker, of Otago University's Department of Public Health, said he did not look at new cases in terms of numbers but the key issue was the trend - it was too early to be concerned.

"It's a bit like the road toll. If you have a bad weekend or a good day, or a bad day, it is the pattern that you're after.

"So what's happening over a pattern of a week or longer and what's happening in these sub-categories. Are we seeing new cases that we don't know anything about or are we seeing just a continuation of these clusters and if so, are other cases likely to keep emerging or not?"

Baker and colleagues Gordon Purdie and Nick Wilson yesterday published an article on Otago's Public Health Expert website setting out the explicit categories they want the ministry to routinely supply.

The categories include people who were infected as a household contact of a known case; people who were infected in a healthcare setting; people whose cause of infection is unknown; people identified as infected during testing of asymptomatic groups.

"We think it is time that the numbers were presented in a way that is a bit more meaningful," Baker said.

"Particularly when this is such a critical issue for New Zealand and there is so much focus on the daily total, we just think it should be split up in a more meaningful way so you can see at a glance what is happening with these numbers."

Two of the new cases are linked to the St Margaret's Hospital and Rest Home cluster, one being a healthcare worker and probable case, and another being a patient and confirmed case who has been transferred to North Shore Hospital.

Previously patients from St Margaret's have been taken to Waitākere Hospital where three nurses caring for them were confirmed as cases this week.

None of yesterday's new cases is related to Waitākere Hospital, a Ministry of Health spokesman said.

Two more new ones in Auckland were linked to known cases, Waitematā DHB was investigating another and a new one Christchurch was linked to the Rosewood cluster.

The death of a former Rosewood Rest Home resident, George Hollings, who was in his 80s was also reported yesterday, taking the total death toll to 20. Eleven of those 20 deaths are from the Rosewood cluster.

Hollings, who was a probable case and had underlying health conditions, died in Burwood Hospital in Christchurch early yesterday, the Health Ministry said.

"His family tell us that George will be remembered as a real Kiwi bloke, a rough diamond, who loved his deer stalking."

Two significant clusters were closed yesterday, one in Wellington and one in Auckland, both of which were related to travel to the United States and both of which peaked at 16 cases.

A Covid-19 cluster is when 10 or more people are infected at the same source event or workplace. They are considered closed if there are no new cases for 28 consecutive days – or two incubation periods for the virus.

The Wellington wedding cluster has already been closed.

New Zealand's first case was confirmed on February 28 and since then there have been 1485 confirmed and probable cases with 85 per cent deemed to have recovered.

In other Covid-19 announcements yesterday the Warriors got approval from Australian border authorities to fly to New South Wales today to begin preparations for a revised NRL league beginning on May 28.

They will be in quarantine in Tamworth for 14 days and some may be away from their families for up to six months.

Education Minister Chris Hipkins has set up a $20 million fund for tertiary and trades training students forced to study online to get access to digital devices and internet connections.

The fund could be accessed through the relevant education organisation such as university, wānanga, New Zealand Institute of Skills and Technology, private training establishments and transitional ITOs,

"Tertiary providers are best placed to work with their learners to identify those most in need during this time," Hipkins said.

He cited a recent survey that suggested 11,150 learners did not have the right devices for distance learning and 11,350 did not have access to broadband at home.