Prime Minister Stephen Harper could call an election as early as this weekend, sources tell 麻豆传媒, which would trigger one of the longest federal campaigns in Canadian history.

Voters head to the polls on Oct. 19, but the official campaign won鈥檛 start until Harper visits Governor General David Johnston and asks him to dissolve Parliament.

So far, Harper remains tight-lipped on when that might happen.

鈥淚 don't speculate and I particularly don鈥檛 speculate on my own actions,鈥 he said Wednesday in an interview with Bloomberg.

The Elections Act requires a campaign to be a minimum of 36 days, but there鈥檚 no set maximum. The last federal election had a 39-day campaign.

If the writ is dropped this weekend, it would mean 11 weeks of campaigning. The record for the longest campaign in modern Canadian history is the 1926 election, which lasted for 10-and-a-half weeks.

And the longer the campaign, the more costly for taxpayers. An extended campaign

Conservative MPs were already fanning out across the country this week to making funding announcements, as the party gears up for the official campaign start.

Employment and Social Development Minister Pierre Poilievre visited Kitchener, Ont., to publicize the government鈥檚 Universal Child Care Benefit -- even directing his message to children at summer camp.

鈥淣ow that we鈥檝e balanced our budget, we can help your mom and dad balance their budget,鈥 he said.

Minister of State John Duncan made a dozen announcements on Wednesday alone.

鈥淵ou can鈥檛 be making announcements during an election period, so this is the window that鈥檚 open,鈥 he told 麻豆传媒 during a stop in Lake Cowichan, B.C.

Meanwhile, NDP Leader Tom Mulcair has already been campaigning steadily in vote-rich Ontario.

麻豆传媒 pollster Nik Nanos said Mulcair鈥檚 strategy appears to be paying off.

鈥淲hat has effectively happened is Stephen Harper and Justin Trudeau have ceded the platform to Tom Mulcair and he鈥檚 taking advantage of it,鈥 Nanos said. 鈥淚t鈥檚 kind of like starting a marathon an hour ahead of your competitors.鈥

Liberal Leader Justin Trudeau is expected to start campaigning next week.

With a report from CTV鈥檚 Deputy Ottawa Bureau Chief Laurie Graham