Defence analyst accuses China of military intimidation over warship sonar incident revealing extent of ‘damage’ to naval divers

The incident, which unfolded on Tuesday last week, saw a run-in between the HMAS Toowoomba and a Chinese People’s Liberation Army-Navy (PAL-N) destroyer in international waters while Australian naval divers were attempting to clear entangled fishing nets from the ship’s propellers.

With the operation underway, the Chinese warship made its way towards the Australian vessel despite being alerted of divers underwater and proceeded to employ its hull-mounted sonar – a high-grade military system typically used for charting deep waters and detecting submerged targets.

Multiple divers sustained injuries due to being subjected to the sonar pulses, who the Department of Defence confirmed on Monday had recovered. However, experts have since weighed in on how the incident could potentially have had far more perilous consequences.

In an interview with Sky News Australia, Dr Malcolm Davis from the Australian Strategic Policy Institute (ASPI) said the effects of active military sonar systems on humans could be close to deadly.

“An active site works by essentially emitting high frequency, high energy sound through the water to basically reflect off a target, which is a submarine,” he told host Peta Credlin on Monday.

“And when you unleash that sort of power in the water against unprotected divers it can cause all sorts of damage to those people. It can cause damage to their ears, but in the worst-case scenario, cause damage to the internal organs and even to the brain.”

The senior ASPI analyst said the Chinese naval contingent “knew exactly the result” its sonar would have on the divers but went on to fire it despite being warned of the operation several times and confirming receipt of the alerts.

Dr Davis drew on instances of similar previous alterations between Australian and Chinese forces and said the incident reflected on Beijing’s longstanding use of military intimidation in the Pacific for gaining strategic advantage, which it ensured was done within the “grey zone” of Defence capabilities.

“I think that what you could see now is the Chinese trying to use a degree of coercion to try and get us to accommodate Chinese interests and there’s one way they can do that and that’s in the grey zone where they use military force below a level which would justify a military response,” he said.

“I think the Chinese have formed on this sort of behaviour whereby on one hand they talk about engagement and diplomacy and stabilisation and then they use their military to put pressure on us and I think the objective of the Chinese here is to intimidate us into perhaps giving more concessions down the track.”

In February 2022, a PAL-N vessel shone a high energy laser at an Australian Air Force jet surveilling the Arafura Sea within Australia’s economic exclusion zone off the Northern Territory coast, following which, in June, a Chinese fighter jet released chaff – a radar countermeasure containing aluminium – in international airspace when intercepting a RAAF aircraft which had been conducting routine maritime surveillance.

However, despite China’s notable assertiveness in the broad South Pacific and the regional security threats it poses, diplomatic responses to the nation’s powerful military remain subdued.

Prime Minister Anthony Albanese came under pressure to answer on whether the HMAS Toowoomba incident was addressed with President Xi Jinping in their meeting on the sidelines of the APEC summit last week.

The PM refused to confirm his discussion with Mr Xi on the issue, but assured Australia “raised it very clearly through all the normal channels”.

“I always speak up for Australia’s national interest and that’s why I’m able to communicate (with China),” Mr Albanese told Sky News Australia’s Kieran Gilbert on Monday afternoon.