The Conservatives have already quietly nominated roughly a third of the party's slate of candidates for the next federal election, a sign that Stephen Harper could be readying to call an election before the fixed date in October, 2015.

While Canadians are expected to go to the polls on the fixed election date of Oct. 19, 2015, general elections are called at the prime minister's discretion.

The Conservatives say they have nominated more than 100 of the party's candidates for 2015, while the New Democrats have nominated just three candidates, lagging behind the Liberals, who have nominated 50.

"That's probably the best signal that the Conservatives, at least internally, have a sense of urgency to try and nominate as many candidates as possible," says pollster and research expert Nik Nanos of Nanos Research.

"It's probably so that they have the flexibility to call the election as planned or to potentially fight an election at an earlier date.

"I would expect the New Democrats, in short order, to catch up — especially with the Liberals in order to focus on swing ridings," Nanos said.

Nanos believes there's "a high likelihood" that the next federal election will be held before the set date.

Nanos, who tracks public opinion weekly, said the numbers show "it's a fairly tight race" between Stephen Harper's Conservatives and Justin Trudeau's Liberals.

"If they see, for example, that if somehow the brand of Justin Trudeau becomes tarnished, or there's a significant misstep, you might see the Conservatives try to pursue a smash and grab victory," Nanos said.

2015 slate unclear

The Conservatives, who have not updated their numbers since mid-May, would not say who the 100 or so candidates confirmed are. 

"We are about a third of the way through and will have a list up on our website at some point this summer," said Cory Hann, director of communications for the Conservative Party.

George Soule, a spokesperson for the New Democrats, told CBC News that three candidates have been nominated to run for the NDP in 2015: Burnaby-Douglas MP Kennedy Stewart in Burnaby South, and newcomers Cheryl Meheden in Lethbridge, and Janis Irwin in Edmonton-Griesbach.

Trudeau showed off some of his newly nominated Liberal candidates before his party's weekly caucus meeting last week.

Liberal candidates in 2015 will include some familiar names, such as former Quebec MPs Alexandra Mendes and Pablo Rodriguez, as well as former Ontario MPs Omar Alghabra, Navdeep Bains and Anthony Rota.

Trudeau said his party is committed to nominating candidates "in the fairest way possible."

"We have advanced real democratic reform by ending the naming of candidates and by replacing this practice with open nominations," he said.

Open nominations

While the three parties have pledged to hold open nominations, the Liberals and Conservatives have faced some complaints within party ranks.

The New Democrats, with 335 candidates left to nominate, argue they are the only party running truly open nominations with their local electoral district associations responsible for recruiting and organizing nomination meetings.

"Handpicking candidates and pretending to be open is a quick way to get candidates, but a genuinely open and member-driven process takes time," Soule said.

Alice Funke, the publisher of punditsguide.ca., a website dedicated to election statistics, has written extensively about the nomination processes of the three major political parties.

Funke said while the parties are conducting candidate nominations in different ways, open nominations are not devoid of involvement by party leaders.

"The central party on behalf of all the other riding associations must get involved and must vet candidates ... and that's not necessarily contrary to open nominations."

Funke argues that while the process varies among parties, all of them exercise some level of control at different stages in the process.

Debra Eindiguer, chief of staff to Green Party Leader Elizabeth May, said the Greens have yet to confirm any candidates but plan to run a full slate in 2015.

"The organizers will be encouraging Electoral District Associations to get their candidates nominated this fall ideally, so we are ready for an early election," Eindiguer said.

June 30 byelections

With the Ontario and Quebec byelections behind them, the federal parties will quickly shift gears and focus their attention on confirming a full slate of candidates for 2015.

On June 30, Canadians in two provinces will go to the polls in four federal byelections: Fort McMurray-Athabasca and Macleod in Alberta, as well as Scarborough-Agincourt and Trinity-Spadina in Ontario.

Advanced voting starts today and continues through to Monday, June 23.

The Conservatives, in a bid to win Scarborough-Agincourt, previously held by the Liberals, put out flyers this week claiming "Trudeau wants marijuana in local stores, just like alcohol and cigarettes."

Trudeau called the attack "misleading and quite frankly disgusting."

The Liberal leader has said that legalizing, regulating and taxing pot would help keep it out of the hands of children and take a lucrative black market product out of the hands of organized crime.

Despite a slow start, the New Democrats say they know there's a lot at stake in the next federal election.

"To keep things in perspective," Anne McGrath, the national director for the New Democrats, said she starts every meeting with an election countdown.

"Anyone working in Canadian politics right now can tell you we've got more work than time," McGrath said in a letter to supporters.