Chris Alexander, parliamentary secretary to the minister of defense, said the HMCS Toronto and Australian vessels had been working together to track drug-traffickers all of last week in the Arabian Sea region of the ocean before coming upon the boat Friday.
The HMCS Toronto tracked the boat, which was flying an unidentifiable flag, overnight before boarding it, Cmdr. David Patchell said.
"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," he said.
The naval boarding party discovered 500 bags of heroin, which officers said they believed was being transported from Afghanistan to a port in Africa, the Canadian Broadcasting Corp. reported Sunday.
"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," Patchell said.
The boarding party destroyed all but a small sample of the heroin, which will be kept for future investigations, the CBC reported.