The NDP says co-operation between opposition parties that would see candidates stand down in certain ridings – an idea that’s been touted by Liberal leadership hopeful Joyce Murray – would be undemocratic.

The NDP recently rejected a call from the Green Party asking them not to run a candidate in the Labrador riding vacated by former Conservative cabinet minister Peter Penashue.

Deputy NDP leader Megan Leslie says not running a candidate in the riding would be unfair to voters.                                 

“Frankly, if anybody should be stepping down it should be Peter Penashue,” Leslie told CTV’s Question Period on Sunday. “We really believe this is a moment where folks can exercise democracy. If they want to vote NDP, they can. If they want to vote Liberal, they can. This is about giving people that choice.”

Tory MP Penashue won the seat from long-time Liberal MP Todd Russell by a mere 79 votes in 2011, but he quit his post earlier this month after Elections Canada found his election campaign had accepted 28 ineligible donations.

The Conservatives have already announced that Penashue will seek re-election in the byelection, which has yet to be called.

Meanwhile, following a conversation with Murray, the Green Party announced it would not run a candidate in the Labrador riding, and urged the NDP to follow suit to rally votes behind the Liberals.

Leslie said she takes issue with candidates winning hard-fought riding nominations, only to have the party swoop in and ask them to step down.

“That’s not democracy,” she said.

Murray contends co-operation between the Liberals, NDP and Green Party -- which she has advocated for throughout her Liberal leadership bid -- is exactly what’s needed to unseat the Conservatives.

“We cannot change the system as long as we keep splitting the vote in so many ridings across Canada and delivering majority government -- a false majority -- to Stephen Harper. And that’s the risk in 2015 again,” she said.

NDP Leader Thomas Mulcair has rejected the idea of co-operation with the Liberals, however Murray maintains that many NDP voters are in favour of the idea.