Canada's Supreme Court has upheld a Quebec regulation banning the sale of margarine coloured yellow.

Unilever Canada had sought a ruling striking down Quebec regulations which prohibit the sale of margarine the same colour as butter. But the Supreme Court upheld decisions of the Quebec Superior Court in 1999 and the Court of Appeal in 2003, it said.

According to newspaper reports, Unilever had argued in court that the rule contravened the rules of the North American Free Trade Agreement and the World Trade Organisation.