As a parade of senior Australian and United States commanders and their public affairs teams attempted to stay on message about the “humanitarian” aspects of the biggest military exercise ever in Australia — the shadow of China was cast over every facet of the intensive war gaming.

During a lightning visit to the exercise area on Sunday, Prime Minister Tony Abbott insisted that China appreciated that Australia was an ally of the United States.

Mr Abbott further confused things when he declined to rule out the possible future permanent basing of USA forces in Northern Australia.

The Marine Corps training rotation is scheduled to grow from 1100 now to 2200 in the next few years, but Mr Abbott left the door open for even greater access for USA forces to the deserted and wide-open training ranges of Northern Australia.

When asked specifically if there would be USA forces based in the north the prime minister was noncommittal.

“Let’s see what the future holds. I am not saying there will be more … but they shouldn’t shock or surprise anyone.”

Ask any of the thousands of USA Marines participating in Talisman Sabre — particularly those based on the tiny island of Okinawa in Japan — and they will tell you that the NT and Rockhampton are war games nirvana.