US marines have touched down in the Top End and will train with Australian troops as tensions in the Pacific continue to heighten.
Up to 2500 marines will conduct combined exercises over the next seven months, some of which will include co-operation with regional partners.
Defence Minister Richard Marles says the rotation is indicative of the strong alliance between Washington and Canberra.
"Our co-operation with the US has been instrumental to enhance the capability and interoperability of both nations through joint exercises and activities," he said.
Mr Marles said the rotation would continue to provide opportunities for Australian industry.
The rotational force's commanding officer said the marines would help provide support in the region.
"Our team is postured and ready to advance shared goals, demonstrate the strength and endurance of our alliance and contribute to regional security and partnerships," Colonel Brendan Sullivan said.
Training exercises include humanitarian assistance, security operations and live fire drills.
