There are 6910 new community cases of Covid-19 in New Zealand today.

The Ministry of Health reported a further 16 Covid-related deaths.

There are 836 people in hospital with the virus, including 27 in intensive care.

Of the people whose deaths we are reporting today, one was from Auckland region, one was from Waikato, two were from Lakes, one was from Tairawhiti, one was from Hawke's Bay, four were from Taranaki, one was from Whanganui, two were from Wellington region, three were from Southern.

Six were aged in their 70s, five were in their 80s and five were aged over 90. Of these people, five were women and 11 were men.

Yesterday, there were 5535 new cases in the community and a further 14 deaths were reported.

There were 720 people in hospital with the virus, including 21 in intensive care.

Over the past three days, the seven-day rolling average for community cases has been below 9000. Yesterday it was 8563.

As school returns today, Prime Minister Jacinda Ardern addressed the fact that some schools have indicated students will be punished if they do not wear a mask.

While the Government didn't reintroduce the mask mandate, it was strongly encouraged that students wear masks.

Ardern told the AM show that they had not given the advice that not wearing a mask should result in punishment, but said it was up to schools to determine how they enforce the health measure.

"It's [mask wearing] strongly encouraged and schools determine how they enforce it, that's it."

A principal has described the difficulty of the last school term while struggling to cover staff away sick with winter illnesses and Covid, and he fears the same challenges will face his school this term.

New data shows the number of teacher sick days have increased by more than 50 per cent compared with a year ago as staff isolate at home due to their own or loved ones' infections.

Pat Newman, principal of Whangārei's Hora Hora Primary School, said he has noticed a "huge" difference in staff absences this year compared with last year.

"We've been very lucky to be able to fill most of the classrooms with relievers most days, but that's not happening everywhere. It's been, to be quite honest, a couple of years of hell.

"We limped, with a lot of luck and intervention from somewhere, through to the end of the term. We now start on Monday and I don't want to be limping anywhere but I suspect we might be."

Hamilton Boys' High School headmaster Susan Hassall said staff absences had been more noticeable this year due to a mix of winter illness and Covid-19.

"On some days, it has been difficult to staff the school fully.

"At our worst, we would have 20-25 staff away [last term] out of 150. We're very fortunate with the quality of our relievers and the impact would be greater on rural schools where they don't have the same relief pool that we are fortunate enough to have."

Speaking to RNZ, Top of the South Secondary Principals Association chair Richard Dykes, tumuaki of Nelson College, said staffing and ongoing disruption to learning would be the biggest challenges as schools reopened.

"That disruption is becoming cumulative and what I'm hearing from schools from my region but also further afield around South Island and New Zealand is the fear that we've got students who are already saying 'look, given the amount of disruption - this is probably our most at-risk students - that's it, I'm signing out'."

Dykes said in term 2, schools had been averaging about 20 per cent of staff absent on any given day and teachers had been having to give up free periods to cover classes.

"I think principals are really worried that we just got through to the end of term pretty much at breaking point.

"If we pick up from there and carry on at that same rate there's a real concern among principals that the impact on our staff is going to be significant."