TORONTO -- Ontario's top doctor said he wouldn't be surprised to discover more cases of the Omicron variant but doesn't see the province implementing further public health measures at this time.

Chief Medical Officer of Health Dr. Kieran Moore made the comments at a news conference on Monday morning, less than 24 hours after confirming two positive cases of the B.1.1.529 COVID-19 variant, which was first detected in southern Africa.

The cases were found in two people from Ottawa who had returned from a trip to Nigeria through an airport in Montreal.

They were the first cases of the Omicron variant identified in Canada.

On Monday evening, Ottawa Public Health confirmed two more cases of the variant, bringing the total number of confirmed Omicron cases in Ontario to four. Public Health said that these cases are unrelated to the first two, although also found in individuals who have recently travelled to Nigeria.

Moore added that two other possible cases have been identified in individuals from Hamilton, although the results of genome sequencing of the two possible cases in Hamilton are forthcoming.

"We are investigating other cases so I would not be surprised if we find more in Ontario," Moore told reporters.

Moore said he does not foresee Ontario taking any steps back in its reopening plan at this time.

"If we see widespread presence of Omicron across Ontario, which is not the case at present, then we could review any measures that we need to take at a provincial level,” Moore said, adding that he doesn't have “a crystal ball.”

"If it's a less lethal virus, less impact on the hospital sector, and our vaccines can continue to work against it, we will continue our current strategy and not have to have any further public health restrictions."

There are also 375 people who have returned to the province in the last two weeks from the seven southern African countries under a federal travel ban, Moore said. The countries include South Africa, Mozambique, Namibia, Zimbabwe, Botswana, Lesotho and Eswatini.

Moore said that local public health units are reaching out to those individuals to ensure they get a COVID-19 test.

The province has extended eligibility for free COVID-19 PCR testing for individuals who returned from those locations between Nov. 1 and Dec. 6.

The variant was first detected on Nov. 24 in a specimen collected on Nov. 9, according to the World Health Organization (WHO) who have since labeled B.1.1.529 as a variant of concern.

Preliminary information appears to show the Omicron variant has an increased risk of reinfection compared to other variants, potentially making it more contagious. At the same time, little else is known about B.1.1.529.

Moore added that it's also currently unclear how Omicron could impact Ontario's hospitals, how severe the symptoms can be or whether the vaccine is effective against it.

"When we saw Delta takeover to be a dominant strain, it was a three to four month transition," he said. "It may be a two to three months transition if it's more infective than Delta and we'll have to put in the precautions that are necessary."

"I know that this news of the variant feels concerning but vaccination in combination with public health individual protective measures has been working to reduce the spread of COVID-19 and its variants in our community."

Moore said that he anticipates a provincial announcement on an "enhanced strategy" regarding vaccination by the end of the week.