Ontario's top doctor says he is asking employers to continue allowing people to work from home whenever possible as COVID-19 cases increase in the province.

Chief Medical Officer of Health Dr. Kieran Moore made the comment during a press conference on Friday, where he addressed the rising case count and announced changes to the province's proof of vaccination system.

"Just as I am asking individuals to continue practicing public health measures and get vaccinated, I’m also asking businesses and organizations to remain diligent and vigilant," Moore said. "We are asking that employers ask their employees to work from home whenever possible."

Moore said when people work from home it helps to reduce mobility in the province, which ultimately reduces disease transmission.

In late November, the City of Toronto announced it would be reopening all of its office buildings at maximum capacity in January and asking employees to return to the office at least part-time.

Mayor John Tory said he hopes that the move will motivate other employers to reopen their workplaces.

The City of Toronto said in a statement to CTV News Toronto they are "reviewing today's provincial announcement."

"Our return-to-office plans are slated to start three weeks from now on Jan. 4. As the City said in its announcement on November 30, decisions are subject to review day-by-day based on science and public health guidance, as has been the case in Toronto throughout the pandemic," city spokesperson Brad Ross said.

Meanwhile, Moore said that Ontario is seeing a sharp rise in cases of the Omicron COVID-19 variant, and this strain now represents 10 per cent of all new infections in the province.

He said projections from Public Health Ontario show that this trend will continue at a rapid pace and Omicron will be the dominate strain by the beginning of January.