OTTAWA - Elections Canada says it will appeal a court ruling that required it to accept a $591,000 GST payback from the federal Conservative party.

The Conservatives went to court to force the agency to take the money, which they said was a product of rebate double-dipping.

The New Year's Eve judgment by the Ontario Superior Court of Justice sided with the Conservatives, and said the party must be allowed to repay the rebates from the 2004 and 2006 federal elections.

Justice Herman Wilton-Siegel ruled that Parliament never intended to treat the GST rebate for non-profit organizations -- including political parties -- as a "subsidy."

He said the practical impact would be to raise the amount of money parties can spend in future elections.

But Elections Canada says the ruling doesn't jibe with its interpretation of the law, hence the appeal.

Wilton-Siegel wrote that the GST rebate is "simply a mechanism for administering the stipulated rate of tax" for non-profits.

"I conclude that general election expenses must be presented net of any GST rebate to the extent required by (generally accepted accounting principles)," he wrote in his judgment.

He said the Tories could deduct from their election expenses the GST that had been rebated by the Canada Revenue Agency.

Elections Canada said it believes the Canada Elections Act requires that reported election expenses reflect their "commercial value," as defined in the act.

Using generally accepted accounting principles would mean that the party's reported expenses would no longer reflect commercial value, the agency said.