Canadian Prime Minister Justin Trudeau will announce Sunday he is calling a snap election for September 20, an official familiar with the plans told The Associated Press.

The source, who was not authorised to talk publicly about the matter and spoke on condition of anonymity, confirmed the election date on Thursday.

Trudeau is seeking to win the majority of seats in Parliament. His Liberal party fell just short of that two years ago and must rely on the opposition to pass legislation.

Trudeau wants to capitalise on the fact that Canada is now one of the most fully vaccinated countries in the world.

Canada's prime minister is less personally popular than he once was but his government's handling of the pandemic has been widely viewed as a success. Canada has enough vaccines for every citizen and the country flattened the epidemic curve while spending hundreds of billions to prop up the economy amid lockdowns.

“Justin Trudeau's accomplishment was to preside over a government that came up with financial, health and unemployment policies that carried us through COVID. That's what he's done and what he'll run on,” said Robert Bothwell, a professor of Canadian history and international relations at the University of Toronto.

Daniel Beland, a politics professor at McGill University in Montreal, noted that Trudeau was criticised for a slow start in acquiring vaccines but is now benefiting from having more than enough for every eligible Canadian.

“They want to exploit this moment,” Beland said.

Beland also said Trudeau is taking advantage of weak opposition.

“Trudeaumania is over. If the Liberals get a majority government it will be in part because of the weakness of the opposition parties. The conservatives are divided,” he said.

The 49-year-old Trudeau, the son of the late iconic Liberal Prime Minister Pierre Trudeau, became the second-youngest prime minister in Canadian history when he was first elected with a majority of seats in Parliament in 2015. He reasserted liberalism in 2015 after almost 10 years of Conservative Party government in Canada, but scandals combined with high expectations damaged his prospects.

His father served as prime minister from 1968 to 1984 with a short interruption and remains one of the few Canadian politicians known in other countries.