OTTAWA – A number of traditional Conservative Party supporters have written a joint letter to Prime Minister Stephen Harper asking him to kill Bill C-51, the government’s controversial anti-terror legislation.

“Bill C-51 creates a domestic spy agency designed to target all Canadians,” they write. “Do you really want to live in a C-51 Canada that you don’t govern? We thought not. We don’t either. Kill Bill C-51.”

READ MORE: Terrorism, Radicalization main threats to Canadian security: spy agency

The letter is signed by traditionally conservative organizations like the National Firearm Association and Free Dominion, as well more than fifty individuals. It was facilitated by OpenMedia, the group behind the public campaign against the anti-terror legislation.

The groups warn Harper’s Bill C-51 will cost the Conservative Party at the polls.

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“They could drain off enough votes to deny the CPC a victory and lead to the return of the Liberals, or insert the New Democrats or a coalition into government,” they write.

Bill C-51 is headed to third reading and final approval, but it has generated controversy since its introduction in January.

If passed into law, the legislation would expand Canada’s spy agency’s powers, and allow for easier information sharing between government agencies.

WATCH: NDP asks Tories to stop pushing C-51

Public Safety Minister Steven Blaney insists the new tools are needed to combat the growing threat of terrorism.