A Vice Media reporter must give the RCMP background materials used for stories on an accused terrorist, Ontario's top court orders.

The Court of Appeal says a judge was right to decide that police must be able to investigate a serious crime.

Reporter Ben Makuch, backed by various media and rights groups, had fought the production order.

He argued if police use journalists to further criminal investigations, sources would be reluctant to come forward.

The materials in question relate to Makuch's stories in 2014 on a Calgary man accused of various terrorism offences.

The Appeal Court agreed with a lower court judge that there is a strong public interest in the effective investigation of such serious allegations.