A number of current and former NDP MPs have approached party president Marit Stiles to express frustration with leader Tom Mulcair's performance, saying it is time for him to step down and hand the reins of the party to someone else.

But Mulcair says he has heard no word from anyone in the party suggesting he is a drag on the NDP's fortunes and that he plans to remain as leader until a new one is chosen next fall.

"There's no question that the entire caucus has been spoken to, and I've been speaking to them consistently throughout the summer in great numbers, and support is extremely strong and I am very happy," Mulcair said Thursday in an interview recorded with host Chris Hall for CBC Radio's The House.

NDP vice-president Hans Marotte, however, said Stiles called him earlier this week saying she had heard from a number of people who wanted Mulcair to vacate his leadership of the party.

"I was quite surprised when Marit told me that some MPs, and maybe some ex-MPs, wanted Tom to leave his position," Marotte told CBC News. "So now I am on the phone the last couple of days asking people if it is still the same thing, if you still want Tom to be leader."

"We have a retreat in a couple of days in Montreal … in the middle of next week. We'll see where the MPs stand," he added.

We do not have another person of his calibre to do that kind of job - NDP vice-president Hans Marotte

At the NDP convention in Edmonton in April, party delegates voted in favour of proceeding with a leadership election by a vote of 52-48 per cent in favour.

According to then NDP party president Rebecca Blaikie, Mulcair needed 70 per cent support to avoid a leadership contest. After the vote, Mulcair agreed to stay on as leader until a new one could be chosen by the party.

The party's leadership contest will be held in the fall of 2017. Nominations open July 2 of this year. Candidates must stump up a $30,000 registration fee and can spend no more than $1.5 million on their campaign, with 25 per cent of all donations going into party coffers.

Rumblings from within

Current and former NDP MPs as well as party supporters, who spoke to CBC News on condition of anonymity, expressed frustration with Mulcair's low profile over the summer and said they were aware of discussions within the party about whether Mulcair should leave sooner rather than later.

Others within the party, however, said they are unaware of any move to oust Mulcair from his position before a new leader is chosen next year.

Marrotte said that none of the people he has spoken to expressed a desire for Mulcair to leave. He said Mulcair is the best person to hold the job until a new leader can be chosen in the fall of 2017.

"The problem is sometimes two, three or five persons says he's not the good guy anymore, and then there's some kind of spiral that's going and people say, 'OK maybe, maybe' and then it happens," Marotte said. "But for me, the question for me is, he is the best guy, we do not have another person of his calibre to do that kind of job."

MP keeping an 'open mind'

NDP MP Nathan Cullen said he does not sit at the leadership table and has had no conversations about the viability of Mulcair's leadership, but that the party is "not in the space we want to be."

Asked if he would support Mulcair's continued leadership, Cullen said that "mostly, I'm on Tom's side, in a sense" and he would see what happens in Montreal.

"I'll go into Montreal with a completely open mind," Cullen told CBC News. "When we get there we meet as a team and I try to talk less and listen more and know that what comes out of there is something we will all get behind, whatever the scenario is."