The US will begin flying its deadliest fighter plane, the F-22 Raptor, out of northern Australia next year, the most senior American commander in the Pacific has revealed as he warned of a need to show strength to deter aggression in the region.

During a visit to Sydney on Wednesday, the commander of the US Pacific Command, Admiral Harry Harris, vowed the US would remain a major player in the region, saying its "enduring interests" would not "change on January 20th" - referring to the day of Donald Trump's inauguration as President.

Admiral Harris revealed that he had signed a 2017 agreement for Australia to host US military assets including the Raptors, which are feared and revered as the best fighter planes in the world, and will send a strong signal about US military presence in the region.

"I think that's positive," Admiral Harris told the Lowy Institute event.