Australian Prime Minister Tony Abbott has approved plans to procure the Northrop Grumman MQ-4C Triton Unmanned Aerial Vehicles.
The sale makes Australian the first foreign customer for the maritime variant of the Global Hawk which can remain airborne for 33 hours, would be based in the southern city of Adelaide.
According to reports, the deal is value to be an estimated £1.6 billion, but Abbott said the details of how many and when had yet to be finalised.
"These aircraft will patrol Australia's vast ocean approaches, and work closely with other existing and future Australian Defence Force assets to secure our ocean resources, including energy resources off northern Australia, and help to protect our borders," he said.
"They will provide the Australian Defence Force with unprecedented maritime surveillance capabilities, operating at altitudes up to 55,000 feet over extremely long ranges while remaining airborne for up to 33 hours."
Australia is expected to use the drones to patrol far over the Indian Ocean, which has become one of the world's most vital energy supply routes, according to the Telegraph.
Canberra recently announced plans to buy eight new Poseidon aircraft for Aus$4 billion. "Given that Australia has responsibility for something like 11 per cent of the world's oceans, it's very important that we've got a very effective maritime surveillance capability," Abbott added.