Police do not have the automatic right to conduct strip searches when they arrest people, Canada's highest court has ruled.

Thursday's 5-4 decision overturned a Toronto man's conviction for trafficking cocaine. Ian Golden was forced to submit to a strip search after a raid on a restaurant in 1997.

"A strip search is a much more intrusive search," Justice Frank Iacobucci and Justice Louise Arbour wrote for the majority.

"Accordingly, a higher degree of justification is required in order to support a higher degree of interference with individual freedom and dignity."

Golden was arrested after undercover detectives witnessed two drug transactions, according to police. Officers frisked him but found no illegal substances. He was taken to a basement staircase, where his pants were pulled down and police spotted clear plastic wrap between his buttocks.

The suspect refused to co-operate with police, court was told, and customers were ordered out of the restaurant. Golden was brought back upstairs and bent naked over a table. Police failed to remove the package, which eventually came out when he defecated.

The Supreme Court of Canada ruled that the strip search was not carried out in a reasonable manner. The judges noted that the police station was only a "two-minute drive" away.

"In our view, it seems highly improbable that the appellant, who was handcuffed, could have somehow surreptitiously ridded himself of the evidence," they wrote in their 51-page decision.

The judges said police did not have the right to conduct the search of Golden's body the way they did simply because the suspect resisted.

"The appellant's refusal to relinquish the evidence does not justify or mitigate the fact that he was strip searched in a manner that showed considerable disregard for his dignity and his physical integrity," they ruled.

Golden has already finished his 14-month sentence for trafficking.

The court called on Parliament to set clear guidelines on strip searches, which it said should be conducted at police stations unless there's reason to believe the suspect is hiding a weapon.