The commander of more than 80,000 US marines in the Pacific is urging Australia to join operations against Islamic State (IS) militants in South-East Asia.

Lieutenant General David Berger is visiting Australia to check on readiness for the Talisman Sabre military exercises off the Queensland and Northern Territory coasts.

He told the ABC the "movement of violent extremist organisations" was a "very real problem" for countries like the Philippines, Malaysia and Indonesia.

The Hawaii-based commanding general of US Marine Corps Forces Pacific said he expected Australian forces could soon join American personnel fighting Islamic extremists in this region.

"Both of us have a long history of being an expeditionary force when needed, so we begin from a common point I think and we've operated alongside for 100 years," General Berger said.

"Regionally where you're looking for stability, where you're looking to reassure other countries that there will be a strong enough force in the region to deter bad behaviour, I think absolutely yes — we would go where asked."

The visiting US general warned that Australia's neighbours would need assistance if they were to successfully stop the threat posed by IS-inspired militants. "I think the potential for it to spread is there, we should not underestimate it," he cautioned. "It's a different kind of a threat than North Korea but it's also a threat that moves in order to survive — it doesn't own a state so it's mobile.