An Australian warship has seized heroin with an estimated street value of $132 million off the coast of Somalia, the Defence Department says.

The 449 kilogram haul was found on a dhow, a type of sailing vessel, intercepted by HMAS Darwin while patrolling the Indian Ocean some 40 nautical miles off Somalia's east coast.

The ship's commander Terry Morrison said the seizure "removed a major source of funding for terrorist and criminal networks which included Al Qaeda, the Taliban and Al-Shabaab".

The drugs were hidden in 20 bags, each weighing between 20 to 25 kilograms.

Defence Minister David Johnston has congratulated the crew of HMAS Darwin who performed the seizure.

"Our naval personnel are operating with a multinational naval partnership in a campaign to defeat terrorism, prevent piracy, reduce illegal trafficking of people and drugs, and promote the maritime environment as a safe place for mariners with legitimate business," Senator Johnston said.

"It is arduous and difficult work and I have been advised the ship's company performed an outstanding and professional job and they should be extremely proud of their efforts."

HMAS Darwin near a vessel which was found to have $132 million worth of heroin on board. ( Defence: LSA Stephen McGreal )

HMAS Darwin is part of Combined Maritime Forces (CMF), a naval partnership involving 30 nations that patrols 2.5 million square miles of international waters.

The Australian ship enforces maritime security with a focus on terrorist activity in the Middle East and Indian Ocean regions as part of the British-led Combined Task Force (CTF) 150, which operates under the CMF.

The bust, the CMF's seventh "significant seizure" this year, came three weeks after the Australian and British navies jointly found 1,032 kilogram of heroin - their largest-ever haul - on a dhow off the coast of east Africa near Kenya and Tanzania.

The drugs were estimated to have a street value of $289 million.

ABC/AFP