Sino-Australian tensions became further strained after an Australian aircraft was lasered while conducting a freedom of navigation exercise earlier this year.

But Air Marshal Robert Chipman says while Chinese military actions in the region continue to be unsafe, they are not expected to increase in frequency.

"Recent encounters with the Chinese have been robust, to say the least," he said.

"Certainly, we have seen a recent spate of unsafe incidences, but it's not a trend line that we can see sustained."

Secretary of the US Air Force Frank Kendall says China's increasing militarisation in the South China Sea is an attempt to develop capabilities to keep nations away from its shores.

"It has big implications for peace and stability in the region," he said.

"We're in what I consider to be a race for military technological superiority with the Chinese."

Hosting his counterpart in Canberra on Monday, the air chief is mulling the extent to which to incorporate a long-range strike capability to counter China's expanding military presence.

The United States would consider extending its expertise in the area to help develop Australia's capability, the secretary said.

"If I saw you had a requirement for long-range strike (capability), then we'd be willing to have a conversation with (Australia) about that," Mr Kendall said.

This could include cooperation on developing the long-range B-21 stealth bomber.

"I don't think that there's any fundamental limitation on the areas in which we can cooperate," Mr Kendall said.

Air Marshal Chipman also flagged a greater role for armed drones in Australia's military.

"China has a formidable aerospace capability and they have concentrated that aerospace capability in the South China Sea region to deter others from going into that airspace," he said.

"That doesn't make it impenetrable. That doesn't mean you can't deliver military effects to achieve your interest when you're up against China.

"Certainly, when it comes to the armed drones, we see unmanned air vehicles as having a significant role in our future."

The two nations will also continue cooperation on hypersonics, but the pair noted the technology isn't a military panacea.

"They will have a role in our inventory of munitions. They have features that are attractive, they get where they're going very fast," Mr Kendall said.

"But they're also very expensive and the range of targets they're useful against is limited. So while I believe that hypersonics will be part of our inventory, I don't think they're going to dominate."

Australian Associated Press