HMAS Darwin has seized more than a tonne of heroin valued at almost $A290 million from a smuggling boat off the coast of Kenya.
Degfence said in a statement that 1032kg was discovered by the Australian warship aboard a dhow in the Indian Ocean, about 27 nautical miles east of Mombasa.
HMAS Darwin's crew spotted the vessel on Wednesday and a boarding team found 46 sacks of heroin hidden among bags of cement.
HMAS Darwin is part of Combined Task Force 150, one of three multinational task forces conducting security and counter-piracy operations in the Indian Ocean and Persian Gulf.
AAP reports Australian warships have already destroyed large quantities of heroin, hashish and amphetamines during patrols off Africa in the past year.