Canada's largest city was plagued by flooding, power outages, and major property damage late on Tuesday after days of torrential rains hit Toronto.

Many of the city's main roads, as well as key transport hub Union Station were shut down due to flooding.

Images from the city showed vehicles submerged up to their roofs, and rescue workers attempting to reach people trapped in their cars and in elevators.

"We're actively rescuing people that are trapped in their cars or on top of their cars," Deputy Fire Chief Jim Jessop told reporters in the afternoon. "We are triaging based on life safety."

Emergency services have also issued warnings about flooding in the greater Toronto area, home to nearly 6 million people.

Toronto Mayor Olivia Chow expressed alarm, according to the Canadian Press news agency. 

"We really seriously have to deal with climate change because these kinds of days are going to be a lot more frequent," Chow told reporters, promising to review the city's flood protection plans.

Scientists have long warned that climate breakdown is going to make extreme weather, such as flooding, more common.

es/rmt (AP, dpa)