Officers from China's People's Liberation Army (PLA) have confronted Australian Deputy Prime Minister Richard Marles at an international security conference over Australia's criticisms of Beijing's military build-up.

Mr Marles, who is also the defence minister, used a speech at the annual Shangri-La Dialogue in Singapore to call out China for its recent confrontations with Australian naval forces, as well as to express concern over the country's aggression towards the Philippines and provocation of Taiwan.

"Actions by Chinese vessels in the West Philippine Sea, such as the use of water cannons and the ramming of Philippine vessels, are a serious escalation of tensions," Mr Marles told the room of senior defence officials and ministers.

"China's behaviour towards Taiwan creates similar concerns. People's Liberation Army exercises that practice attacks and blockades of Taiwan do not inspire confidence that China prioritises — or is planning for — a peaceful settlement to the status of this island and its 22 million people.

"Activities that the Australian Defence Force has conducted in the region for decades, safely and consistent with international law, are increasingly contested by the PLA."

A middle-aged man in a suit with grey hair speaks behind a lectern in front of a blue screen. — Mr Marles raised concerns about China's military build-up during his speech.(AP Photo: Vincent Thian)

In response to Mr Marles's speech, PLA officer Hanwen Ge, who was in the audience, said China cooperated with countries in the region.

"Since the end of the Cold War, China has never been at war against its neighbouring countries," he said.

"As a sovereign country, China has the natural right to defend its national security."

Another PLA member, Qichao Zhu, said there were "at least two mistakes" in his speech.

"Taiwan is one province of China, and we will not endanger the Taiwan people's security and life," he said.

"You didn't mention that the Philippines, their ship, intentionally collided with China's coast guard ships.

"The rules of law is a very important concept. China sticks to the rules of law."

Following the speech, Mr Marles met with his Chinese counterpart, Dong Jun, where he raised his concerns face-to-face.

A crowd of people, mostly Chinese men in military uniform, walk down a corridor. The man in the centre is wearing blue. — Chinese Defence Minister Dong Jun, centre, at the Shangri-La Dialogue.(AP Photo: Vincent Thian)

Philippines warns of growing risk of war

It was not just Australia that expressed concerns over China's acts of aggression in the region, with Philippine President Ferdinand Marcos Jr warning of dangerous consequences if Chinese militia vessels continued to challenge his nation's territorial waters.

"If a Filipino citizen is killed by a wilful act, that is, I think, very, very close to what we define as an act of war," he said.

An older Filipino man in a grey suit sits on a stage in front of a blue screen and gestures as he speaks. — Philippine President Ferdinand Marcos Jr (left) also criticised China's conduct.(AP Photo: Vincent Thian)

United States Defense Secretary Lloyd Austin also addressed the conference, insisting the "United States can be secure only if Asia is secure".

"Every country, large or small, has the right to enjoy its own maritime resources," he said.

"The harassment the Philippines has faced is dangerous, pure and simple. We all share an interest in ensuring the South China Sea remains open and free."

Mr Marles's speech also addressed China's support for Russia, saying it "raises important questions about the role it intends to play as a global actor".

"As China steps up to a larger role, it must accept, like all great powers, that there will be much greater scrutiny on the way it uses its strength and which countries it chooses to partner with," Mr Marles said.

"There has been a view, sometimes expressed by Chinese officials, that its strategic partnership with Russia is a necessary buffer against anti-China hostility. That is totally wrong."

Opposition frontbencher Dan Tehan said Prime Minister Anthony Albanese should be playing a bigger role in making Australia's concerns known.

"We have to be prepared to stand up to China when they put our national interest at risk," he said.

"We need the prime minister to be the one standing up and saying to China: 'We need you to abide by the rules-based order, and we need you to abide by international law.'"

Ukrainian President Volodymyr Zelenskyy is also attending the conference, where he plans to meet Mr Austin, take part in a panel discussion on Sunday, and ask attendees to support a peace summit to be held later this month in Switzerland.

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