Stephen Harper's Conservative Party was the big winner on Monday, winning two of four byelections -- including a rural Quebec riding that favoured the Bloc Québécois.

The upset came in Montmagny-L'Islet-Kamouraska-Rivière-du-Loup, where Conservative Bernard Généreux claimed 42.7 per cent of the vote, elbowing out Bloc Québécois candidate Nancy Gagnon, who won 37.7 per cent, according to preliminary results released by Elections Canada.

That byelection will likely come under scrutiny in the coming days. The Bloc filed a police complaint on Monday, claiming that someone pretending to be their Quebec City MP left halting, unprofessional-sounding phone messages urging people to vote for the Bloc - calls the Bloc claims were designed to leave a negative impression of the party.

The second Tory victory was claimed by Scott Armstrong in the Nova Scotia riding of Cumberland-Colchester-Musquodoboit Valley. Armstrong took 45.8 per cent of the vote, New Democrat Mark Austin took 25.8 per cent, and Liberal Jim Burrows was third, according to preliminary totals.

The Nova Scotia riding was a Tory stronghold until 2007, when former Conservative MP Bill Casey became an independent after being booted out of the Tory caucus in 2007 for criticizing the budget.

Coquitlam City Councillor Fin Donnelly held a sizeable lead over Port Moody Councillor Diana Dilworth in New Westminster-Coquitlam. Donnelly won 49.6 per cent of the vote to Dilworth's 35.8 per cent. Liberal Ken Beck Lee finished a distant third, with 10.3 per cent, followed by Green Rebecca Helps, with 4.3 per cent.

Bloc Québécois candidate Daniel Paillé handily won the east Montreal riding of Hochelaga, smashing NDP hopes of an upset by Jean-Claude Rocheleau. Paillé 51.2 per cent of the vote to Rocheleau's 19.5 per cent. Liberal Robert David was third, followed by Conservative Stephanie Cloutier.

Federal Liberals were shut-out in Monday's byelection, finishing third in all four contests. None of the ridings have traditionally been Grit territory.

Monte Paulsen reports for The Tyee.