The federal Liberals have an important role to play in unifying Canada, interim leader Bob Rae said Tuesday, hours before the polls closed in a Quebec provincial election that could see the election of a sovereigntist government.

"There's a continuing responsibility on our part to be a party that is a clear voice for unity, a clear voice for a federal country and a clear voice for effective leadership," Rae said as his party's MPs arrived in Montebello, Que., for their annual retreat.

"I choose to comment on elections after they've taken place. I've already told people that I very much want to see a federalist result in Quebec and I hope that that happens. And if there's another decision by the voters of Quebec, we'll have to deal with that," he said.

Liberal MPs will spend the next two days discussing strategy for their return to Parliament on Sept. 17.

But talk of the party's impending leadership race is likely to overshadow much of the planning that comes out of the caucus meetings.

The Liberals are set to choose a new leader next year.

MPs in leadership race should keep critic files: Rae

Rae says he thinks Liberal MPs running for the party's leadership should be able to keep their critic files.

The party is expected to release the rules for the leadership race later this week, including campaign spending limits, on which Rae refused to comment.

He said he would tell the caucus that their colleagues in the leadership race shouldn't have to give up their Commons responsibilities, which take a lot of time but also give them more face-time in the media and with party members who will be voting on who should take over from Rae.

"I don't think they should be required to stay away from the House of Commons. I think they should be encouraged to continue to participate in the life of the caucus, continue to be effective spokespeople for the Liberal Party of Canada. We need all hands on deck as we go forward and I'm going to continue to make that recommendation to the caucus," Rae said.

The NDP, which chose leader Tom Mulcair last March, shuffled its caucus last fall as MPs declared their intention to run for the party's leadership. Many candidates said they were relieved they wouldn't have to juggle their critic files with committee and constituency work as well as crossing the country for the leadership race.

Plan to add 30 seats to House 'crazy'

Rae held a wide-ranging question and answer session with reporters to kick off the two days of caucus meetings. Asked about a plan to add 30 new seats in the House of Commons, Rae said it's wrong for Canada to keep increasing the size of the House of Commons every time the census shows the country has grown.

"It costs a lot of money. It's a ridiculous rearrangement. We have to completely redesign the House of Commons, keep adding offices everywhere, staff everywhere, it's a total waste of money," he said.

Instead, the government should re-divide up the existing 308 seats based on changing population counts in ridings across the country, Rae suggested. The plan to add more seats exists "because it's the course of least resistance and because no one has the wherewithal to say, well some provinces will get a little bit less, others will get a little bit more."

"And it's crazy. At some point you say look this doesn't make sense."