Canadian Prime Minister Justin Trudeau won a second term in Canada's national elections on Monday, losing the majority but delivering unexpectedly strong results despite having been weakened by a series of scandals that tarnished his image as a liberal icon.

Trudeau's Liberal party took the most seats in Parliament, giving it the best chance to form a government. However, falling short of a majority meant the Liberals would have to rely on an opposition party to pass legislation.

"It's not quite the same as 2015. It's not all owing to the leader," said Robert Bothwell, a professor of Canadian history and international relations at the University of Toronto.

"Trudeau is prime minister because the rest of the party was able to pull itself together and prevail. While Trudeau certainly deserves credit for what has happened he's really going to have to demonstrate qualities that he hasn't yet shown."

Still, the results were a victory for Trudeau, whose clean-cut image took a hit after old photos of him in blackface and brownface surfaced last month.

"I'm surprised at how well Trudeau has done," said Nelson Wiseman, a political science professor at the University of Toronto.

"I don't think anybody expected Trudeau to get a majority but they are not that far off."

With results still trickling in early on Tuesday, the Liberals had 157 seats 13 short of the 170 needed for a majority in the 338-seat House of Commons.

"Tonight Canadians rejected division and negativity. They rejected cuts and austerity. They elected a progressive agenda and strong action on climate change," Trudeau said early on Tuesday.

His address to supporters came, unusually, as his Conservative rival, Andrew Scheer, had just begun speaking to his own supporters, forcing networks to tear away from Scheer's speech.

But the prime minister struck a conciliatory note: "To those who did not vote for us, know that we will work every single day for you, we will govern for everyone," Trudeau said.

In his concession speech, Scheer said the results showed Trudeau was much weakened since his 2015 election, when pundits had predicted the beginning of another Trudeau dynasty.

"Tonight Conservatives have put Justin Trudeau on notice," Scheer said. "And Mr Trudeau when your government falls, Conservatives will be ready and we will win."

Trudeau's Liberals will likely rely on the New Democrats to form a new government and pass legislation. Opposition New Democrat leader Jagmeet Singh said early today that he had congratulated Trudeau and vowed to play a constructive role in Parliament.

Ahead of the vote, polls showed a neck-and-neck race across the country as Trudeau, who took power as a charismatic figure promising "sunny ways," battled Conservative leader Scheer for the chance to form the next government.

Trudeau, 47, the Liberal Party leader, was endorsed by former US President Barack Obama in the final stretch of the campaign and is viewed as one of the last remaining progressive leaders among the world's major democracies.

But he was shaken during the campaign by a blackface scandal and has been dogged by criticism of his handling of a corruption case involving a major Canadian construction company. Trudeau, the son of the late Liberal Prime Minister Pierre Trudeau, has also had to overcome a sense of fatigue with his government.

Trudeau, accompanied by his family, voted in Montreal on Monday after a marathon sprint campaigning across the country in the past four days. Scheer voted in his Saskatchewan electoral district.

On Twitter, Trudeau repeatedly urged people to get out and vote. Voter turnout is crucial for the Liberals, who privately fear low engagement will affect them more than the Conservatives.

"(A minority government) would force people to talk to each other, which is what we need," said Naomi Higgins, a 25-year-old voter in Toronto who supported the Liberals four years ago but switched to the Greens in this election.

"We need to [...] start doing what's best for everyone instead of what makes one party or the other look best."

The Greens were leading or elected in one seat, while the separatist Bloc Quebecois were leading or elected in 33 seats in the province of Quebec.

Liberal campaign strategists say four members of Trudeau's Cabinet could lose their parliamentary seats, including Public Safety Minister Ralph Goodale, a veteran member of parliament who is seen as one of the government's heavyweights.

Goodale, 70, is the only Liberal member of parliament from the western province of Saskatchewan, where anger at Trudeau is mounting over federal environmental policies that the energy industry says will harm output.

The oil industrys top lobbying group has blamed Trudeaus policies for throttling investment in the sector, and some global energy companies have shed assets in the oil sands region of Alberta, the country's main oil-producing province.

Canada's economy, however, has been on a general upswing in 2019.

The Canadian dollar has been the best-performing G10 currency this year, rising more than 4 per cent against its US counterpart, as the economy added jobs at a robust pace and inflation stayed closed to the Bank of Canada's 2pc target.