Defence Minister Richard Marles says the interception of one of Australia's maritime surveillance aircraft by a Chinese fighter plane over the South China Sea last month was a "very dangerous" situation.
In a statement, the Department of Defence said on 26 May a RAAF P-8 maritime surveillance aircraft was intercepted by a Chinese J-16 fighter aircraft during a routine maritime surveillance activity in international airspace in the South China Sea region.
"The intercept resulted in a dangerous manoeuvre which posed a safety threat to the P-8 aircraft and its crew," it said.
Prime Minister Anthony Albanese says the government has expressed its concerns with the Chinese government through appropriate channels.
"The Australian government has raised our concerns about the incident with the Chinese government," Mr Albanese told reporters in Perth
"We are concerned about this incident. We have expressed those concerns through appropriate channels.
"I won’t be making further comment on it, other than to say that in the Australian government’s view, in the defence department’s view, this was not safe, what occurred, and we’ve made appropriate representations to the Chinese government expressing our concern at this."
Mr Marles said the Chinese J-16 aircraft flew very close to the side of the Australian plane, where it released flares.
"The J-16 then accelerated and cut across the nose of the P-8, settling in front of the P-8 at very close distance," he told reporters in Melbourne on Sunday.
"At that moment, it then released a bundle of chaff, which contains small pieces of aluminium, some of which wee ingested into the engine of the P-8aircraft. Quite obviously, this is very dangerous."
Mr Marles said the Australian crew was unharmed, and Australia would "not be deterred" from continuing activities in the South China Sea.
"The activity of the P-8 form part of maritime surveillance activity which has been undertaken by Australia in the South China Sea for decades; other countries do the same," he said.
"The South China Sea matters to Australia. It matters to Australia because most of our trade traverses the South China Sea. And so, as a nation, we are deeply invested in the UN Convention on the Law of the Sea, we are deeply invested in the rights of freedom of navigation in the South China Sea."
The department said Defence has for decades undertaken maritime surveillance activities in the region and does so in accordance with international law, exercising the right to freedom of navigation and overflight in international waters and airspace.
Opposition Leader and former defence minister Peter Dutton said the incident was concerning.
"This is a very serious time, and we will support the government in whatever actions they need to take to keep our country safe," he told reporters in Brisbane, where he was announcing his coalition frontbench.
"An act of aggression, as we have seen here, is not dissimilar to what we have sent on a regular basis in the East China Sea."
He has appointed Western Australian MP and former SAS member Andrew Hastie as opposition defence spokesman.
