KITCHENER -- Waterloo Region's top doctor says local vaccine supply won't be enough to stop a third wave of COVID-19.

"While vaccine supply has improved and vaccination clinics are ramping up in Waterloo Region, there will not be enough supply coming in the next few weeks to be the solution to avert a third wave," Medical Officer of Health Dr. Hsiu-Li Wang said at the region's COVID-19 update on Friday.

On Monday, the Ontario Hospital Association sent out a tweet saying the province is now in the third wave of the pandemic.

In the tweet, officials with the OHA said "strong adherence to public health measures is urgently needed to prevent overwhelming hospitals."

Also on Monday, Ontario's Chief Medical Officer of Health Dr. David Williams said the province is "into that base of a third wave." However, he said what that means and how big that wave will be is still to be determined.

Dr. Gerald Evans, an infectious disease specialist, said the third wave is emerging in Waterloo Region and across Ontario.

"The thing we have learned about COVID-19 is that it behaves similarly around the world," he said. "Right now, Europe is right into the third wave and we are typically about four weeks behind Europe."

Evans also pointed to an increase in the seven-day average for new cases, along with a higher test positivity rate.

"It got very low at one point, down to about two per cent," he said. "We are now getting close to four per cent."

The Ministry of Health reported a 3.8 per cent positivity rate on Monday after performing 33,900 tests in the past 24 hours. The seven-day average for new cases is now up to 1,349 across Ontario, an increase from 1,155 a week ago.

Waterloo Region reported 26 new cases Monday. Ontario added 1,268 cases of the disease.

"The Kitchener-Waterloo area is at a particular risk because of its proximity to Toronto, where most of these new cases are," Evans said.

Wellington-Dufferin-Guelph Public Health said people need to continue following public health measures to prevent transmitting the disease and more contagious variants.

"For us, right now, it really is a race against these new variants that are more transmissible and the vaccination effort," said Dr. Matthew Tenenbaum, associate medical officer of health with WDG Public Health.

With files from CTVNewsToronto.ca and CTV Kitchener's Natalie van Rooy