As voters in Toronto prepare to soon cast their ballots in two federal byelections, the battle for the downtown riding of Trinity-Spadina heated up Saturday as Justin Trudeau and Tom Mulcair both made campaign stops in the area.

Byelections in the ridings of Trinity-Spadina and Scarborough-Agincourt are set to take place on June 30.

The riding of Trinity-Spadina, previously held by NDP MP Olivia Chow until she stepped aside to join the Toronto mayoral race, has proven to be a critical battle ground for both the Liberals and New Democrats.

Long-time city councillor Adam Vaughan announced his plans to run for the Liberals back in April, while the NDP threw their support behind candidate Joe Cressy, the son of two former city councillors.

On Saturday, Vaughan was joined by Trudeau at a riding event, where the Liberal Leader said he was confident in Vaughan’s chances.

Trudeau noted that the NDP may have a tough time gaining traction in Trinity-Spadina after the June 12 Ontario election, which saw Liberal candidate Han Dong snatch the provincial seat from long-time NDP MPP Rosario Marchese.

Trudeau said the victory was a sign that voters are looking for a change.

"We're taking it as a very positive sign. During the provincial election, Adam and Han Dong … worked very, very closely, combining volunteers, working to help each other out and to make sure that Trinity-Spadina turns red," Trudeau told The Canadian Press.

"Obviously there's a continuation of that."

On the other hand, NDP Leader Tom Mulcair said critics shouldn’t be quick to jump to any conclusions.

During a campaign stop in Toronto’s Chinatown with Cressy, Mulcair noted that Ontario’s provincial election results were based on campaign-specific issues and should not be used to predict the outcome of a federal byelection.

"It was a provincial election. People had their own take on what was necessary to stop Tim Hudak and his mad idea of starting off his campaign by proposing to fire the breadwinner in 100,000 Ontario families. People made their own decisions based on that," Mulcair said.

"I realize a lot of people who were torn as they were voting in the provincial election are all coming back to the fold. They understand that the only progressive voice in Ottawa is the NDP."

Both Trudeau and Mulcair have popped up in the riding multiple times since the byelections were called last month. Mulcair also hit the hustings with Cressy on Friday.

Other candidates running in the riding of Trinity-Spadina include the Green Party's Camille Labchuk, Conservative Benjamin Sharma, and independent John Turmel.

Candidates in the Toronto-area riding of Scarborough-Agincourt are also gearing up for election day.

The riding has been held by Liberal Jim Karygiannis since 1988, but Karygiannis announced he was resigning his seat in the House of Commons in April in order to run for city council in Toronto’s municipal election in October.

Arnold Chan is the riding's new Liberal candidate. He is facing Conservative candidate Trevor Ellis, NDP candidate Elizabeth Yin Long, Green Party candidate Shahbaz Mir and independent Kevin Clarke. None of the candidates have run in the riding before.

The official vote takes place on June 30 from 9:30 a.m. to 9:30 p.m. Polling locations can be found on voter cards that were mailed to residents on June 6, or by entering a postal code online.

Advance polls opened Friday for those planning to be out of town on the 30th, which falls after the first weekend of summer break and just before the July 1 Canada Day statutory holiday.

Polls will remain open on Saturday and Monday from noon to 8 p.m.

To vote on election day or advance voting days, residents must be already be registered, or can register at the polling location before voting. Voters must be able to prove their identity and address.

Byelections will also be taking place on June 30 in the Alberta ridings of Fort McMurray-Athabasca and Macleod.

With files from The Canadian Press