OTTAWA - Liberals are demanding the federal Tories slash ties with a polling firm censured by an industry body for breaching codes of conduct in a campaign targetting former Liberal justice minister Irwin Cotler.

An independent complaints commission censured Campaign Research after it concluded the company "likely diminished public confidence in the marketing research industry" after it called Cotler's constituents and suggested he was stepping down, which wasn't true.

A complaints panel of the Marketing Research and Intelligence Association probed the company's actions after seven complaints surfaced in the fall of 2011.

Cotler, who represents the Mount Royal riding in Montreal, raised concerns about the calls in the Commons a year ago.

The voter identification poll was commissioned by the federal Conservative party.

Conservative MPs have not denied involvement in the calls, but party spokesman Fred Delorey said Wednesday he wouldn't comment on "internal party matters."