A Canadian warship has made a major drug bust after intercepting a boat transporting approximately $100-million worth of drugs in the Indian Ocean.

The Department of National Defence says HMCS Toronto seized around 500 kilograms of heroin from a boat on Friday. The exact location of the incident was undisclosed because it's part of an ongoing Canadian Forces counter-terrorism operation.

"This is a big blow against some serious drug networks and Canadians should be proud that their sailors were central to a really unprecedented seizure," Chris Alexander, parliamentary secretary to the minister of defence, told CBC News.

HMCS Toronto's commanding officer told CBC News his first crew tracked the ship overnight, which was flying an unidentifiable flag, before boarding it.

"Very quickly on we ascertained they were not being truthful about their mission, their voyage, so we continued on with a full search of the vessel and discovered the drugs," Cmdr. David Patchell said.

The drugs were found in 500 bags after a naval boarding party searched the vessel.

Patchell noted this as one of the largest heroin seizures on the seas and said a large portion of the world's narcotics originate in southwest Asia and "very possibly these drugs could have ended up on Canadian streets."

Alexander told CBC News that Canadian and Australian vessels had been working together all week to interrupt drug trafficking in the Arabian Sea.

"Several boats were hailed and board," he said, adding that the boat was likely carrying Afghan heroin destined for a port in Africa.

The drugs seized by the crew was destroyed aboard the ship but a small sample has been kept for future investigations.

Canada's naval ships have been patrolling the Indian Ocean and Horn of Africa since the September 11 attacks.

HMCS Toronto left Halifax in January. It is currently part of a international naval task force patrolling the Arabian Sea and Indian Ocean.

"There's definitely a link between these narcotics and terrorism and by stopping narcotics on the high seas, especially in this quantity, we know that the financial nodes of terrorism are being attacked," said Patchell.