OTTAWA -- New Democrat MPs in the House of Commons could be without a permanent leader on Parliament Hill until after the federal election in 2019 if Ontario legislator Jagmeet Singh takes over at the party's helm.

Should he win the leadership in October, Singh told The Canadian Press he would prefer to forego seeking a Commons seat until the next election two years hence, opting instead to spend time reaching out to Canadians and visiting different parts of the country.

Singh has spent much of his leadership campaign billing himself as a "growth candidate" whose fresh approach and lack of federal experience would ultimately attract a host of new supporters to the New Democrat fold.

"I would be happy to spend the time while I am not a sitting member to campaign across the country, to get to know the issues, to get know the different ridings ... spending that time speaking with people, reaching out to them," he said.

"I would run for a seat in 2019."

Such a move would be reminiscent of Jack Layton, who was crowned NDP leader in 2003, but did not seek a seat in the House of Commons until the federal election the following year.

Layton died of cancer not long after navigating a milestone 2011 election campaign that elevated the NDP to official Opposition status for the first time in its history.

Singh said he'd be "open to hearing more advice" on whether or not to seek a seat sooner, "but personally I am not concerned."

NDP international trade critic Tracey Ramsey, an Ontario MP elected in 2015 who threw her support behind Singh earlier this week, said she sees no issue with the would-be leader choosing to bide his time.

"I think his plan to be out in Canada -- really building our party, building our membership, talking to people in their communities -- is critical," Ramsey said.

The caucus could easily find a capable deputy leader among its 44 members who could "hold it down in Ottawa" while Singh did the work of building grassroots support, she said.

"I think it will be the best of both worlds to have that type of model."

Other members of the NDP caucus have lined up behind Singh recently, including Brian Masse, an Ontario MP elected in 2002, as well as B.C.'s Alistair MacGregor, Kennedy Stewart, Randall Garrison, and Jenny Kwan.

Earlier Friday, nine fellow members of the Ontario legislature also joined the Singh camp: Catherine Fife, Wayne Gates, Michael Mantha, Peggy Sattler, Taras Natyshak, Lisa Gretzky, Percy Hatfield, Cindy Forster, and Jennifer French.

"These are my colleagues, people that I have worked with," Singh said. "They know the way I work and they know how much I respect them."

The race to replace Tom Mulcair as federal NDP leader is getting more serious, with a Thursday deadline looming for each contender to sign up new party members.

Rank-and-file members will start casting ballots online Sept. 18 -- though it remains unclear precisely when it will become clear who the new leader will be.

First ballot results will be revealed Oct. 1 in Toronto; anyone with more than 50 per cent of the vote will be the winner. Otherwise, the results of a second ballot will be released in Montreal Oct. 8. A third ballot is scheduled for Oct. 15 in Ottawa.

Other candidates in the running to replace Mulcair include northern Ontario's Charlie Angus, Niki Ashton from Manitoba and Quebec's Guy Caron.

Angus said Friday he has been pleased to receive support from members of the organized labour labour movement --long a mainstay of federal NDP politics.

The president of the Public Service Alliance of Canada issued an open letter this week, endorsed by a number of other labour leaders, saying no one questions Angus's commitment to the party's "traditional values."

"Historically, labour has played a huge role in our party ... but in recent years, I think there has been, at times, a relationship on both sides that hasn't been as close," Angus said. "Labour leaders are looking for a party that has their back."

The leadership race will come down to who is resonating most with the base, he added.

"Our message is resonating and we are going to stick with that message and keep doing that work on the ground."