Prime Minister Justin Trudeau says Canada is closing its borders to most people who aren't Canadians or permanent residents to slow the spread of COVID-19.

Trudeau says the government is taking `increasingly aggressive steps'' to keep everyone safe on the advice of public health.

Experts, with the move to close the border coming just days after Health Minister Patty Hajdu said border closures have not proven particularly effective elsewhere.

The restrictions come into effect March 18, and do not apply to Americans because the two countries are so closely intertwined.

"Trudeau says Canadians who are not in Canada need to come home immediately and is establishing a fund to help people who are finding it financially difficult to arrange travel home in the face of soaring ticket prices."

"Travellers still must isolate themselves for 14 days after they arrive. The government is also restricting overseas flights to just four airports in Toronto, Montreal, Calgary and Vancouver, and mandating airlines to screen passengers for symptoms of the virus before allowing anyone to board a plane."