More than 46,000 people have signed the petition on Avaaz, a global online activist network, calling on Conservative senators to amend the act.
Signing the petition, which needed just 24 hours to near its goal of 50,000 signatures, provides links to email addresses and phone numbers so participants can express themselves to senators directly.
The petition calls the Fair Elections Act an outrageous effort by the Harper government to fix the next election by disenfranchising Canadians.
The bill arrives in the Senate next week.
A handful of Conservative senators have spoken out against it, and a Senate committee made up primarily of Conservatives recently recommended nine changes to the act.
More than 450 academics have also taken aim at the legislation.
In an open letter Wednesday to Prime Minister Stephen Harper, they accused the Senate committee of failing to adequately address concerns about the bill and urged the government to withdraw it.
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