The Lakes District Health Board says the region is "currently in the peak of Omicron" which could last until about mid-April.
A Covid-19 modeller agrees and said it is "possible" the region has reached peak cases or is just about to.
Meanwhile, Ministry of Health data shows the region's Covid cases in the past 14 days have seen a "peak, dip, increase".
Yesterday, 330 new Covid-19 community cases were reported in the Lakes region with eight people in hospital.
Toi Te Ora Public Health on Friday reported 274 new cases in Rotorua District and 142 in Taupō.
There were 3605 active cases in the Lakes District Health Board area as of Friday.
Toi Te Ora said with differences in reporting systems, report timeframes, and as case information was updated, there may be some discrepancies in numbers such as with Ministry of Health data.
A Lakes District Health Board spokesperson said it estimated the region was in the peak of Omicron which could last until about mid-April. Hospitalisations were usually 10 days behind cases.
The spokesperson said it was "difficult to say" why there was a drop in positive cases recently and then a rise.
"It is possible people are not self-reporting RATs."
But it looked like there was "a weekend effect" across the country when less testing happened, then numbers picked up again in the week.
People who tested positive for Covid with a RAT should report it via My Covid Record online, the spokesperson said.
The board also encouraged people to get vaccinated when eligible for their first, second or booster dose.
Covid-19 modeller Professor Michael Plank said it was "possible" the Lakes region had reached peak cases based on his own data of the midland region. This encompassed several district health boards in the central North Island including the Lakes, Bay of Plenty and Waikato.
"If you look at the cases for that region ... the number of cases is lower than it was seven days ago. And that's generally a reasonable indicator that things have peaked.
"The numbers will bounce up and down but I would expect the trend to start to come downward from here on."
Plank said case numbers would "bounce around" due to how many people decided to get tested on a particular day, which was often lower on the weekend.
He said a dip and then a rise could be "a weekend effect".
But in his view, the Ministry of Health data looked "pretty flat".
"They will bounce around from day to day obviously but I don't think there's really a sign of it going steeply upwards again."
Te Punaha Matatini principal investigator and Covid Modelling Aotearoa project lead Dr Dion O'Neale said the ministry data showed case numbers had done a "peak, dip, increase".
He suspected this happened after there was a change in Covid testing.
"Once RATs became available, a bunch of people rushed out and got them.
"These people weren't able to get PCR tests previously and then suddenly they could get a RAT and we saw this big surge.
"In the background, people's inclination to seek a test has fallen off we suspect," he said.
People not reporting their test results could also be a reason, he said.
"We know there are a bunch of people who are buying their own RATs ... test positive and then just don't log the result."
This was especially the case for those under 12 years old, he said.
But given the dip and then rise in cases again, O'Neale suspected the region had not hit the peak of Omicron yet.