A second wave of Omicron is starting - but experts say it could be worse than the first as more elderly are getting infected.
It comes as 152 new cases were reported in the Te Whatu Ora - Lakes, formerly Lakes District Health Board, region on Tuesday - the highest number of daily cases in the past month in the region.
While yesterday's district case numbers were not available at deadline, 10,290 new community cases of Covid-19 were reported nationally.
The last time daily cases were above 10,000 was April 21.
University of Auckland senior lecturer and principal investigator at Te Punaha Matatini Dr Dion O'Neale said more elderly getting Covid was "concerning" as they were at risk of more severe health outcomes.
O'Neale said the second wave could be worse than the first in March, as it was affecting people who were more vulnerable.
"It's also coming at a time when it's not just Covid that we've got circulating now.
"Back in March, we had ... very little influenza and other respiratory illnesses."
Before the second wave started, O'Neale said hospitals were already "pretty busy" with such illnesses, particularly influenza.
O'Neale said people could still get reinfected due to the new variants BA.4 and BA.5 circulating in the community.
"People shouldn't be thinking, 'hey I've had Covid, I'm not going to get it infected or I've got 90 days until I get reinfected' ... it's very much a case of not just trying to avoid it but trying to avoid getting infected as many as times as possible."
Covid-19 modeller Professor Michael Plank said it appeared a second wave was coming which would likely last "a month or two".
"In March, we had that big wave but it was very heavily concentrated in younger people ... whereas now we have seen a steady shift in older age groups.
"It is concerning that if this second wave predominantly affects older groups more than the first wave did, that could result in quite high levels of demand on our healthcare system."
"The vaccine is still the best tool we have to fight this virus."
University of Waikato professor of public health Ross Lawrenson said an increase in cases could be due to "mask fatigue," travelling, and people staying inside more due to the colder weather.
Asked if New Zealand should move to the red traffic light setting, Lawrenson said this was a political decision rather than a public health decision.
"From a public health point of view, it would be nice to make masks compulsory and restrict movement around and try and restrict the spread, not only of Covid but also influenza.
"But I don't think that practically, society ... is up for that."
Prime Minister Jacinda Ardern was asked about the cases in Sydney yesterday and said the most meaningful way to make an impact was with boosters, vaccinations and mask use.
A move to red would only restrict gathering limits. The current situation would not likely be improved by such a move.
A second vaccination booster shot is now available for all Kiwis over 50. Health, aged care and disability workers 30 years and over, and immunocompromised people are also eligible.
A Te Whatu Ora-Lakes spokesperson said a second wave of Covid would be challenging, but its staff and GPs would do their best to manage patients and only admit those who needed to go to hospital.
Influenza was also starting to decrease in the community, the spokesperson said.
The spokesperson said the second booster was "strongly recommended" for anyone aged over 65, as well as Māori and Pacific peoples older than 50 and people who were severely immuno-compromised.
"Covid is not going away and vaccination is as important now as ever in reducing likelihood of contracting Covid and the severity of the disease.
"We continue to urge anyone, including children over five, who is not yet fully immunised, to complete their immunisations.
"It remains just as important as ever to wear masks, practise social distance as appropriate, and maintain good hygiene habits."
Last week, Rotorua Hospital's Older Persons and Rehabilitation Service ward was closed to new admissions and visitors, and Taupō's Inpatient Unit was closed to visitors due to a Covid-19 outbreak.
Today, the spokesperson said the Rotorua Hospital ward was now open. The Taupō inpatient unit had three stable patients admitted with Covid and continued to have visitor restrictions.