Prime Minister Justin Trudeau and Ontario Premier Kathleen Wynne joined a provincial byelection rally in Whitby, Ont., on Tuesday evening with hopes of painting a longtime Tory riding Liberal red.

Ontario's transportation minister, Steven Del Duca, and several other Liberals also joined the rally in support of the party's candidate, Elizabeth Roy. The event — which was criticized by both the PC and NDP candidates in the riding — was held just two days before the Thursday night vote. 

Trudeau and Wynne entered the venue, Zingers Sports Bar, together, navigating their way through a crowd that chanted "Trudeau! Trudeau! Trudeau!"

"How amazing is this?" Roy asked the crowd as she took the stage. 

This is the first time in 30 years the Liberals have had a real shot in the riding, Roy told her supporters.

"We're going to paint this town red. Whitby-Oshawa is going red."

Trudeau reminded the hundreds of supporters on hand of last fall's federal election, which saw a major change in fortune for the Liberals, and said his government is making good on its promises more than 100 days in.

He praised Roy as a strong leader who will help work on key Liberal issues like creating middle-class jobs and reforming the pension system.

"You expect a strong voice at Queen's Park," Trudeau said, flanked by Roy and Wynne.

PCs have controlled riding

It's unusual for a prime minister to wade into a provincial byelection, but Ontario Premier Kathleen Wynne took a high-profile role in Trudeau's campaign in the recent federal election, which apparently paid off. 

The Liberals, who held only 13 seats in the province when the federal election was called, were elected in 80 of Ontario's newly expanded total of 121 seats.

The Whitby-Oshawa byelection was triggered after Progressive Conservative Christine Elliott resigned the seat, months after losing her party's leadership race.

Lorne Coe, the PC candidate, said his party won't give up the riding without a fight.

"I'm certainly going to continue the legacy of public service of Christine Elliott and her late husband, Jim Flaherty," he said.

Elliott had held the riding since 2006.

The Liberals are eager to snatch the long-held Tory riding away, though the result won't change the balance of power in the provincial legislature.

Ontario Progressive Conservative Leader Patrick Brown and the NDP candidate have called Trudeau's appearance in Whitby-Oshawa a "distraction."

Niki Lundquist, the NDP candidate, said the prime minister's appearance is a sign of weakness.

"It's interesting to me that Kathleen Wynne is so desperate to shore up her candidate that she reaches out to Trudeau to cause a distraction," she said.

Candidate hoping for a boost

Liberal candidate Elizabeth Roy said she is looking forward to welcoming Trudeau and Wynne to the riding. 

"To have the prime minister and premier visit in the final days of the campaign is a great validation of the work we've done," she said. 

Polls have suggested the race is between Roy and Coe — both regional councillors. 

The NDP hopes MPP Jennifer French's win in the neighbouring riding of Oshawa in the 2014 general election is a positive sign for the party, but Lundquist has been polling significantly below the Liberals and PCs.

Éric Grenier, CBC polls analyst and ThreeHundredEight.com founder, said the byelection appears to be a race between the Liberals and PCs.

But Grenier said, "It's unlikely to change anybody's minds just because Justin Trudeau is visiting the riding."

With files from The Canadian Press