Australia's most significant logistics exercises with the United States since World War II have officially kicked off, aiming to build stronger relations between multiple military allies.
More than 30,000 defence personnel from 13 countries will take part in Talisman Sabre, which began in Sydney on Friday and will go for two weeks.
Originally involving Australia and the US, the biennial exercises have expanded to nations including Japan and South Korea.
Defence Minister Richard Marles said some of the drills would be the most significant logistical exercises in Australia since the Second World War.
"All of this is building muscle memory between our two country's defence forces," he said.
"It's building comfort and familiarity, not just between Australia and the United States, but the other 11 countries that will be participating in the course of Exercise Talisman Sabre.
"It's about ensuring we are becoming much more familiar with each other and able to operate at a higher level, in a much more coordinated way."
Defence forces from Canada, Fiji, France, Germany, Indonesia, Japan, New Zealand, Papua New Guinea, the Republic of Korea, Tonga and the United Kingdom will participate in the exercise.
Personnel from India, the Philippines, Singapore and Thailand are attending as observers.
Chinese spy ships will closely watch the exercises with vessels from the People's Liberation Army-Navy sitting on Australia's coast.
Chief of Joint Operations Lieutenant General Greg Bilton said the drills were not about China, but about the nations involved.
"It's about our partner nations, building interoperability, being able to build trust and an ability to respond together to whatever crisis might exist in our region in the future," he said.
"So we're entirely focused, frankly, on our alliances and our partnerships and building much better levels of capability."
Talisman Sabre director Brigadier Damien Hill said the Chinese ships would be free to come into Australia's exclusive economic zone.
Opposition defence spokesman Andrew Hastie said it was worrying the Chinese ships could be used for spying.
But Lt Gen Bilton was not concerned about China monitoring the exercises.
"They've come before ... they've done this for a number of years and we're well prepared for it," he said.
The exercises have already hit a snag, with live firing drills due to take place at Jervis Bay off the NSW south coast delayed because of bad weather.
Mr Marles and Foreign Minister Penny Wong will hold talks with their American counterparts on the sidelines of Talisman Sabre as part of the annual AUSMIN summit.
Talisman Sabre was officially opened at Sydney's Garden Island naval base with manoeuvres taking place in NSW, Queensland, the Northern Territory and Western Australia.
