The US military has flown two Boeing B-52 bombers into Darwin ahead of multi-national war games hosted by the Australian Defence Force (ADF).

The B-52s, weighing more than 125,000 kilograms each, will form the tactical backbone of a training exercise dubbed Pitch Black, according to military officials.

Two teams made up of men and women from the US armed forces have also arrived in the Top End to take part in the exercise.

The simulated conflict will involve long-range tactics in the vast, empty airspace between Darwin and Katherine.

US Marines began arriving in the Territory on a six-month rotational basis in mid-2012 and have since undertaken joint training exercises with the ADF.

According to a statement, the rotations of US military equipment and personnel in the Pacific region "enhance US ability to train, exercise and operate with Australia and with other allies and partners across the region, further enabling the US to work together with these nations to respond more quickly to a wide range of challenges, including humanitarian crises and disaster relief, as well as promoting security cooperation efforts across the region".

Decisions on future rotations remain under discussion, the statement adds.