OTTAWA - Charles Gonthier, a former Supreme Court judge who served as watchdog over Canada's electronic spy agency, has died.

Gonthier passed away at age 80 on Thursday.

Defence Minister Peter MacKay said Gonthier was "a dedicated Canadian who served his community and country with pride."

Gonthier sat on the Supreme Court of Canada from 1989 to 2003.

In 2006, he became watchdog over the Communications Security Establishment, an Ottawa-based wing of the Defence Department that gathers foreign intelligence through electronic eavesdropping. It has aided the efforts of Canadian troops in Afghanistan in recent years.

MacKay said Friday that Gonthier provided him with valuable counsel on the activities of the spy service. "He will be missed."

Gonthier was born in Montreal on Aug. 1, 1928, the son of Georges Gonthier and Kathleen Doherty.

He earned his law degree at McGill University in Montreal and went on to a heavily decorated career that took him to the highest legal bench in the land.

Gonthier was named to the Supreme Court of Canada on Feb. 1, 1989, after being appointed to the Quebec Court of Appeal the previous year.

He first became a judge at the Quebec Superior Court in 1974.

Gonthier was known for dissenting from the court's majority, offering a more conservative interpretation the individual rights guaranteed under the Charter of Rights and Freedoms.

In 1999, he argued in a dissent that provincial legislation excluding same-sex couples from the legal definition of marriage did not breach the Charter.

The best-known decision in which he wrote for the majority of the court was the Thibaudeau v. Canada in 1995, a ruling that upheld Income Tax Act provisions that taxed the recipients, not the payers, of alimony and support monies.

Gonthier retired from the Supreme Court on July 31, 2002 -- the day before he turned 75, the age at which high court judges must hang up their scarlet robes.

He went on to join the Montreal law firm of McCarthy Tetrault and was appointed commissioner of the CSE on his 78th birthday.

Gonthier married his wife, Mariette Morin, in 1961. The couple had five sons: Georges, Francois, Pierre, Jean-Charles and Yves.