Commander of Australia's Joint Task Force 633, Brigadier Nagy Sorial, said it was the second largest haul ever by the Combined Maritime Forces (CMF), a 30-nation naval partnership which patrols 2.5 million square miles of international waters.
"The weekend's find made Australia's maritime contribution to CMF one of the world's most effective current heroin interdiction forces," Sorial said in a statement.
HMAS Newcastle intercepted a stateless dhow off the east African coast where her boarding party uncovered the drugs, the statement added, without saying which country's shoreline it was closest to.