Prime Minister Tony Abbott says improving defence co-operation means Chinese troops could exercise with Australian forces and even US Marines.

Chinese troops could end up exercising alongside the diggers in Australia’s north, perhaps even in conjunction with US Marines.

Prime Minister Tony Abbott raised the possibility in the final press conference of his north Asia trade trip in Beijing, declaring these issues had been “well and truly discussed”.

He said Australia’s already strong defence ties with Japan and South Korea had now strengthened further.

“Here in China, as a result of this trip, I am now quite confident that we won’t just have high level meetings between our respective militaries,” he said.

“We will have exchanges and exercises between our respective militaries and also multilateral exercises.”

That had to be good for peace and understanding in the region and wider world, he said.

Mr Abbott said he would not speculate on who else could be involved in exercises involving Chinese forces.

“Thanks to the rotating elements of US Marines in Darwin, there’s potential for multilateral exercises in Australia involving the US,” he said.

When Australia and the US announced the program of training US troops in northern Australia in 2011, China expressed strong concerns.

Mr Abbott said that was then, not now, and the issue was not the troop rotation but that it had come as a surprise at the time.

“Once people were fully aware of what was happening, the concerns fairly quickly dissipated,” he said.

Starting from a low base, Australian defence ties with China have expanded steadily in recent years.

Australian and Chinese defence leaders hold annual talks and Australian and Chinese warships have staged reciprocal port visits.

In late 2012, Australia hosted exercise Co-operation Spirit, featuring a small number of Australian, New Zealand and Chinese People’s Liberation Army personnel.

This didn’t involve troops with weapons against a pretend adversary. Rather, participants practised disaster relief and medical procedures at Enoggera Barracks in Brisbane over four days.

For the first time, Chinese forces will participate in this year’s US-hosted RIMPAC, the world’s largest maritime exercise staged on and around Hawaii in June and July. However, PLA involvement will be limited to exercises in disaster relief.