Health officials in Ontario on Saturday said two confirmed cases of the new coronavirus variant first detected in the United Kingdom had appeared in the Canadian province.

Scientists said the variant is about 40-70 percent more transmissible than the original strain. Several other countries, including Australia, Italy and the Netherlands, say they have also detected cases of the new strain.

The Canadian cases, identified in a couple in southern Ontario with no known travel history, exposure or high-risk contact, came as the province went into a lockdown on Saturday.

"This further reinforces the need for Ontarians to stay home as much as possible and continue to follow all public health advice, including the provincewide shutdown measures beginning today," Dr Barbara Yaffe, Ontario's associate chief medical officer, said in a statement.

Ontario reported 4,301 new cases over the past two days, with the province seeing more than 2,000 cases per day for 12 consecutive days.

Last week, Canada extended to January 6 a ban on passenger flights arriving from Britain and expanded enhanced screening and monitoring measures to travelers arriving from South Africa, citing the rise of the more infectious variant.

Scientists say there is no evidence that vaccines currently being deployed – including one made by Pfizer and BioNtech – or other COVID-19 shots in development will not protect against this variant.

Canada began rolling out the Pfizer vaccine earlier this month and started distributing Moderna Inc's COVID-19 vaccine across the country last Thursday.

Canada has so far reported 541,616 cases of COVID-19, including 14,800 deaths.