Aotearoa is likely to see a "significant" wave of Covid-19 as we head into winter, a virus modeller says.
A new subvariant of Covid-19, called FLiRT, has begun circulating around the motu.
Professor Michael Plank, from the University of Canterbury, said it looked as if FLiRT - sometimes referred to as FLip - was driving Covid numbers up internationally and there were signs that was starting to happen in Aotearoa as well.
There had been a "rapid increase" in Covid hospitalisations in the past couple of weeks, with about 240 people in hospital with the virus, up from 120 a couple of weeks ago, he told Checkpoint.
"It has risen quite quickly which does suggest that we are heading into a significant wave."
Covid-19 Modeller says new variant threatens wave in NZ
At the same time, there had been "quite a big jump" in the levels of Covid being picked up in wastewater testing, Plank said.
There were 6146 new cases of Covid reported in the past week - almost double the 3922 cases reported the week before.
FLiRT was closely related to the JN.1 subvariant, which caused the wave that hit New Zealand over Christmas.
There was no indication the subvariants caused more severe illness or different symptoms, but they appeared to be more transmissible than earlier forms of the virus.
Plank said it was "bad timing" as Aotearoa headed into flu season, with the wave likely to peak in June or July.
"The timing is a bit concerning in the sense that hospitals have always been busy at this time of year and we're now adding Covid into the mix," he said.
"That could put quite significant pressure on our healthcare system."
The good news was that vaccines were still likely to be "really effective" against the new subvariants, Plank said.
He encouraged everyone to stay up to date with their vaccinations, including getting a flu jab and a Covid booster if eligible.
Everyone over 30 could get a free booster if they had not had a jab or the virus in the past six months, he said.
"Getting a booster in time for winter is a really good idea to reduce the likelihood of getting really sick with Covid over the coming winter."