The haul, weighing 581kg (1,280lbs), was found aboard a dhow that was intercepted by the HMAS Newcastle off the coast of east Africa.
The Australian vessel is part of the Combined Maritime Forces (CMF), an international patrol mission.
The CMF aims to tackle piracy, terrorism and drug smuggling.
The naval partnership, involving 30 countries, patrols 2.5 million square miles of international waters in the Indian Ocean and around the Middle East.
Brigadier Nagy Sorial, the commander of Australia's Joint Task Force 633, said in a statement that the haul was the second-largest ever by the CMF.
"The weekend's find made Australia's maritime contribution to CMF one of the world's most effective current heroin interdiction forces," he said.
The statement did not say which country's shoreline was closest to the dhow.
An Australian warship has seized heroin with an estimated street value of more than A$520m (US$399m; Â£254m) in the Indian Ocean, a naval official said.