Moving from their previous position, NDP members of the special House of Commons committee on electoral reform say they are open to supporting a referendum on the issue.

Nathan Cullen, the NDP reform critic, said the change in tune is intended — at least in part — to achieve consensus on a path forward among all political parties.

Cullen said testimony before the committee has been overwhelmingly in favour of adopting a system that prioritizes proportional representation. But MPs have learned the public is concerned about how that new system is determined, too, he said.

"We've also heard from Canadians that the way we validate this system is incredibly important and that the notion of a referendum or a plebiscite is important for a large number of Canadians and we acknowledge that," Cullen told reporters on Wednesday.

New Democrats had not ruled-out a referendum previously, but they were reluctant to support a public vote, at least before implementing reform. Cullen had suggested conducting a referendum after a new electoral system was implemented.

"We have some reservations, of course, because referendums are very powerful tools. They have to be handled with a great deal of respect and done properly in order to be effective," Cullen said.

"Yet in order to achieve consensus at this committee, which we believe to be possible, from all of the party's perspectives...we think the option of a referendum should be included in the committee's final report."

Other party positions

The Conservatives and Bloc Quebecois have demanded that a referendum be held before any changes are made. And Green MP Elizabeth May, another member of the committee, has said she is willing to support a referendum, despite her own reservations.

Together, the Conservative, NDP, Bloc and Green MPs constitute a majority of the committee's membership.

"It would be strange if we had a scenario in which the opposition parties were able to make concessions and come to an agreement to help the Liberals fulfill their campaign promise...and have the Liberals opposed to that," Cullen said when the committee's opposition majority was noted by a reporter.

"I think it would be an incredibly powerful signal to Canadians if this committee...was able to come to an agreement across party lines with the interests of Canada first, party a distant, distant second."

The Liberal government has argued that a referendum is not necessary and expressed concern that such a vote could be divisive. Still, ministers have not categorically ruled out conducting one.

Referendum time crunch

A referendum would have to occur in relatively short order. Marc Mayrand, the chief electoral officer, has said Elections Canada would need two years to implement a new system.

The electoral reform committee is in the midst of a week of closed-door discussions aimed at finalizing a report to the House of Commons. The committee must deliver its recommendations by December 1.