The NDP’s previous leader says the new one, Jagmeet Singh, would have a tough time staying on as NDP leader if he loses the Burnaby South byelection.

Former NDP leader Tom Mulcair said, should Singh fail in his bid for a B.C. seat, “it would be extremely difficult for Mr. Singh to stick around.”

“Indications are -- and I’ve talked to people within the party -- they’re comfortable that they can win the riding but they’re far from being confident that they will,” Mulcair told host Don Martin on Wednesday’s episode of CTV’s Power Play.

• WATCH: Jagmeet Singh faces byelection, challenges

Prime Minister Justin Trudeau called three byelections on Wednesday for Feb. 25: Burnaby South in B.C., Outremont in Quebec, and York—Simcoe in Ontario. The announcement came just days after the NDP criticized Trudeau for refusing to call the byelection sooner.

The byelection will be the first public test of the new NDP leader, who took the reins of the party after a leadership race in October 2017.

Should he lose, however, Singh has vowed to stay on as leader of the NDP as the party heads into a federal election in October of 2019.

“I will absolutely be the leader that leads the New Democratic Party to the 2019 general election," Singh told Don Martin during Monday’s episode of CTV's Power Play.

According to Mulcair, this means the party will throw everything it has at ensuring Singh secures a win. If he loses, Mulcair said “it would be very, very difficult for him” to lead the NDP into the fall election.

“I think that anybody who knows anything about politics would agree with what I just said,” Mulcair added.

Because of this pressure, Mulcair said the party will likely throw all of its resources at Singh’s race – which could be to the detriment of the other two byelections.

“The number one place where the NDP is going to be putting its time, money and energy is of course in Burnaby South, where Mr. Singh has finally decided to run in a byelection,” Mulcair said.

“I think that it’s going to be very tough for Julia Sanchez and the NDP in Outremont.”

Outremont is Mulcair’s old riding -- but when he won in a 2007 byelection, the conditions were very different.

“People were getting tired of the Bloc, the Liberals, of course, were still mired in the echo from the scandal involving sponsorship,” he said.

“We had never come anywhere near winning a seat in that type of election in Quebec but we threw everything we had at it and there was a novelty to the NDP.”

However, even if those added resources help bolster a byelection win for Singh, he likely won’t be sitting in the House of Commons until mid-March.

Mulcair said that might be too late for him to make a real impact.

“It’s not very much because in March, for all intents and purposes, we will be in the election. You can expect Justin Trudeau to be using all of the perks of his office,” he said.

However, the former NDP leader said it’s better than nothing.

“It’s certainly better than the situation he’s in now which is -- frankly -- nobody gets a chance to see him and nobody’s paying much attention to what he says,” Mulcair said.