New Zealand has suffered its deadliest day of the pandemic yet, with five new COVID deaths and a doubling of community cases to record levels.

Health officials reported 12,011 community cases on Friday, more than half in Auckland, as cases leapt from 6137 on Thursday and 2365 at the start of the week.

Two of the five deaths occurred in Auckland’s North Shore Hospital, with two more in Waikato and another in Tauranga.

New Zealand’s COVID-19 death toll stands at 61.

Hospitalisations have also doubled from the start of the week.

There are 237 people with the virus receiving care in hospitals, up from 116 on Monday.

With a PCR test positivity rate of 27.4 per cent, it’s likely the actual rate of community transmission is extremely high, and Friday’s case number is a huge undercount.

University of Otago public health professor Michael Baker said the inclusion of rapid antigen tests in case numbers led to the record total.

“Making RATs widely available has meant numbers have jumped a lot,” he said.

“When you make testing more available and less invasive, people’s behaviour changes and they get tested.”

Dr Baker said the inclusion of RAT results made it hard to predict the trend for future counts.

“We can’t be totally sure about the trend … 3000 cases on Wednesday, 6000 cases on Thursday, 12,000 cases today, it’s more vertical than expected … that’s not plausible,” he said.

“It might have been a lag in cases.

“But Omicron will keep breaking records for some time … next week we’ll pass 20,000 and 30,000 perhaps.”

For now, the outbreak remains centred on Auckland, which had 7963 cases, or two-thirds of Friday’s count.

The next worst-hit region is Waikato, Southern (comprising Dunedin, Invercargill and Queenstown), and the Bay of Plenty.

“Auckland will peak sooner and some places are two to three weeks behind. The national peak will be later in March,” Dr Baker said.

“Around half the country is going to be infected in the next two to three months … potentially two million people.”

New Zealand’s record case count means it could soon overtake Australia, with a population five times higher, for COVID infections.

Public health experts predict the peak of the Omicron outbreak is yet to come in New Zealand, which has avoided the worst of the pandemic for two years.

In contrast, cases are broadly trending down in Australia, which hit a peak in January and had 25,703 cases on Thursday.

The scale of infections is forcing New Zealand’s parliament to hold “hybrid” sittings from next week, with some MPs to sit in Wellington, and others to join virtually.

“Now we can safely have all 120 MPs together in the ‘virtual’ chamber, just in a different way,” Speaker Trevor Mallard said.

-AAP