Reyat was handed a nine-year prison sentence last year for lying repeatedly at the 2003 trial of two men charged with mass murder and conspiracy.
He was a Crown witness at the trial of Ripudaman Singh Malik and Ajaib Singh Bagri, who were acquitted in the biggest case of aviation terrorism before the 9-11 attacks in the US.
His testimony was part of a deal that saw him plead guilty to manslaughter in the deaths of 329 people aboard Air India Flight 182 on Jun 23, 1985, Vancouver Sun reported.
His lawyer Ian Donaldson argued that Reyat's conviction should be overturned because jurors weren't required to agree on what he lied about before finding him guilty, says a lawyer.
Donaldson told the BC Court of Appeal that a lack of unanimity among jurors examining 19 alleged lies Reyat told in the 2003 trial of two men accused of mass murder and conspiracy resulted in an unfair verdict.
He said the Crown had laid an improper indictment in the perjury case, laying one count, but alleging 19 different particulars which the judge said the jury could select from in reaching its verdict.
Crown Len Doust argued that Reyat's latest conviction should not be overturned and that all the case law shows that jurors can consider a number of facts in a trial and reach their verdict without agreeing on each and every fact.
Rayat had already served a 10-year sentence for the same-day deaths of two Tokyo baggage handlers who were killed when a bomb-laden suitcase meant for another Air India plane exploded prematurely.
The Air India flight 182 operating on the Montreal- London Delhi route was blown up by a bomb at an altitude of 31,000 feet, and crashed into the Atlantic Ocean while in Irish airspace.