Australian warships are being "routinely" shadowed by Chinese military vessels in contested South China Sea waters, in behaviour the new Chief of Navy describes as "unusual".
In a wideranging interview, Vice Admiral Mark Hammond insisted the interactions with the People's Liberation Army (PLA) remained safe and "professional" and he predicted Chinese spy ships would closely monitor naval drills off Darwin next week.
Exercise Kakadu begins on Monday, with ships and aircraft from more than 20 nations expected to draw the attention of Chinese intelligence-gathering vessels, which have monitored similar activities in recent years.
"The exercise will happen in international waters outside of our territorial seas, and it's not unusual to see ships from many different nations in that environment," Vice Admiral Hammond said.
"We prepare accordingly, and we will scale and manage the exercise accordingly as we have in the past," he added.
The biennial Exercise Kakadu was cancelled in 2020 due to the COVID-19 pandemic but in 2018, before diplomatic relations with Beijing deteriorated, the Chinese warship Huangshan was invited to take part in the maritime drills.
Last year the ABC revealed the arrival of a Chinese auxiliary general intelligence (AGI) vessel off the Queensland coast, which was later joined by a second spy ship to track the Talisman Sabre military exercises.
The Navy Chief declined to speculate on the unlikely chance that China would again be invited to take part in Exercise Kakadu.
"Participation in exercises like that is a political decision," he said.
"At the end of the day, we are where we are, and I am yet to see an Australian ship invited to a PLA Navy exercise."
This month's military exercises in Australia's northern maritime approaches are taking part amid heightened tensions in the South China Sea, and over Taiwan following US Speaker Nancy Pelosi's recent visit to the democratic island.
Earlier this year the ABC revealed Australian warship HMAS Parramatta was closely tracked while sailing through international waters claimed by Beijing. That included being followed by a Chinese nuclear submarine.
Vice Admiral Hammond confirmed it was now standard practice for Australian warships to be closely shadowed by the PLA when they transited through the South China Sea.
"Routinely, whenever we have a ship up there, there's a PLA Navy vessel within sight, quite often following us around. That's unusual behaviour," he said.
"I don't know another navy that does that. It's a departure from what we would call normal maritime behaviour, but it hasn't stopped us from conducting our operations."
Asked if Australian warships were likely to follow the US Navy in sailing through the Taiwan Strait, Vice Admiral Hammond revealed some transits had occurred in the "last couple of years".
"Those decisions are political decisions so, if directed, we'll continue to do them," he said.
Navy Chief plays down 'commentary' on submarine plan
Approaching his first 100 days in the navy's top job, Vice Admiral Hammond also played down a recent warning America's overstretched shipyards might not be able to accommodate building Australia's future nuclear-powered submarines.
Last month the US program executive officer for strategic submarines, Rear Admiral Scott Pappano, issued the blunt assessment as a special AUKUS task force continues to work with the US and UK on options for Australia's next fleet.
Vice Admiral Hammond, a career submariner, argued "there's been a lot of commentary" ever since the AUKUS announcement was made in September last year.
"I would listen to whatever the President of the United States and their authorised spokespeople say on this because I think there's going to be lots of different opinions in lots of different pockets and there's certainly no shortage of opinion and commentary out there."
