A forensic audio expert is casting doubt on an analysis done for the Conservative party of secretly recorded, controversial comments allegedly uttered by a Liberal candidate.

Geoffrey Stewart Morrison says the expert employed by the Conservatives used a flawed, discredited method to analyze audio of a conversation involving Marlo Raynolds, the Liberal candidate in Banff-Airdrie.

Even had an accepted method been used, Morrison says there's no way an analysis could conclude with 100 per cent certainty — as claimed by the party's expert — that Raynolds uttered the comments Conservatives have been using to pillory him.

The audio, surreptitiously recorded by a young Conservative operative at a public meeting last month in Canmore, Alta., involves a conversation about the Harper government's plan to allow income splitting for tax purposes.

A man the Conservatives maintain is Raynolds says the plan would give couples with children money that they'd waste buying television sets and cars, rather than caring for their kids.

Raynolds and Canmore resident Tam McTavish have sworn an affidavit stating that it was actually McTavish who made the offending comments.

Morrison, former director of the forensic voice comparison laboratory at Australia's University of New South Wales, says it would take weeks of work and thousands of dollars to conduct a proper voice-comparison analysis of the poor-quality audio recording.