Conservative Leader Stephen Harper is drawing smaller crowds at recent events because the campaign is urging volunteers to focus on mobilizing the vote in preparation for election day, a campaign spokesman says.

"We are pushing all our volunteers and supporters to knock on as many doors as they can over this last week. I think it's all about ground game and mobilizing our vote at this point," Kory Teneycke told reporters at a campaign stop in Toronto. "And that's what our focus is."

The ability of the parties to get their supporters out on election day could well be the deciding factor in a tight race.

Teneycke said the priority was for volunteers to meet and identify Tory voters, and not to provide a large audience at events for the media.

"At the end of the day, this is a very close race and the ground game is going to matter," he said. "What the spin is to the media and how many people you pull off the doors to be at your events might make it look good, but I don't think it's where the focus needs to be.

"Other campaigns will make their own determination of what the appropriate thing is to do. But that's ours."

Liberal Leader Justin Trudeau had drawn some big crowds at recent campaign stops in Ontario, including a rally in Brampton, Ont., which drew at least 5,000 supporters.

But Teneycke said political rallies generally attract the same sort of people who volunteer in campaigns and are activists. The Liberals have been busing people from all over southwestern Ontario to go to rallies to try to pump up the crowd numbers, he said.

"If you are on a bus travelling from Kitchener to the Greater Toronto Area, well, you're obviously not knocking on doors in Kitchener. We have a different approach, a different strategy. We want our folks working on the ground. That's what we're doing."