"We urge the Australian side to respect the facts, stop making reckless and irresponsible accusations against China," defence ministry spokesman Wu Qian said, adding China "did not engage in any activities that may have affected the Australian divers".

Canberra accused Beijing over the weekend of "unsafe and unprofessional" conduct at sea around the HMAS Toowoomba, a long-range frigate that had been supporting United Nations sanctions enforcement efforts within Japan's exclusive economic zone.

Australian Defence Minister Richard Marles said divers were clearing fishing nets from the ship's propeller when the vessel was approached by a Chinese destroyer that "likely" injured a number of servicemen with its hull-mounted sonar.

Wu said the Australian version of events was "completely inconsistent with the facts", adding China "firmly opposes this and has made solemn representations to the Australian side".

"The Chinese military's 'Ningbo' destroyer took measures such as tracking, monitoring, identification, and verification in accordance with the law and regulations," Wu said.

- 'Strict discipline' -

Earlier on Monday, Beijing's foreign ministry also defended the conduct of the Chinese military, saying it was in line with international law.

"It is hoped that relevant parties will stop causing trouble at China's doorstep and work with China to maintain momentum for improving and developing China-Australia relations," ministry spokeswoman Mao Ning told a regular press conference.

China and Australia have been working to patch up their once-close trading relationship after years of bickering and tit-for-tat reprisals.

Australian Prime Minister Anthony Albanese made a breakthrough trip to Beijing earlier this month, hailing the progress as "unquestionably very positive".

But tensions remain when it comes to security, as Australia draws closer to the United States in an effort to blunt China's expanding influence in the Asia-Pacific region.

The Diving Medical Advisory Committee, an independent London-based organisation, has warned that sonar sound waves can cause divers to suffer dizziness, hearing damage and organ damage.

The HMAS Toowoomba -- commissioned in 2005 -- is a long-range frigate packed with advanced surveillance capabilities and "world class" weapons systems, according to the Australian navy.

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