Anthony Albanese is staring down China and its denial a destroyer set off sonar pulses and injured Australian navy divers.
Several divers from HMAS Toowoomba were in the water off the coast of Japan last week when a Chinese destroyer engaged in what the government labelled an "unsafe and unprofessional" interaction.
That charge has been denied by China, which dismissed Australia's side of the story as "completely inconsistent with the facts" while declaring the warship was always a safe distance away.
The prime minister slapped down that statement when asked if he believed China had carried out the attack.
"I know they did," Mr Albanese told Fox FM on Wednesday.
"The Australian Defence Force and the Navy, we don't put out a statement like that without checking it all.
"It was a dangerous thing to happen and it shouldn't have."
The prime minister, who met with Chinese president Xi Jinping at the APEC summit last week and who has been eager to improve Australia's relationship with China, appeared nonplussed by the denial.
"They always push back. We've said we'll disagree where we must, and we have a disagreement here," he said.
The divers suffered minor injuries to their ears, despite the Australian ship having warned others they were in the area.
Australian Strategic Policy Institute senior analyst Euan Graham said warships were equipped with cameras and surveillance, with activities logged under good practice measures.
"If the government felt confident enough to put out a statement, strongly worded, about unsafe and unprofessional conduct, they would assume they've got good verifiable grounds to do so," he said.
Dr Graham said the incident forced a "course correction" from the Albanese government, which had been at risk of making concessions to China as it attempted to stabilise relations with the superpower.
"Silence is a kind of concession - if Australia doesn't say things or do things about the South China Sea or East China Sea or where the broader order is at stake, then that suits China," he said.
During a press conference in New Delhi on Tuesday, Foreign Minister Penny Wong said the safety and wellbeing of Australian defence personnel was the government's priority.
"We have raised our serious concerns with the Chinese authorities following what we regard as unsafe and unprofessional interaction with the PLA navy destroyer," she said.
China always acted in accordance with international law and practice, foreign ministry spokeswoman Mao Ning told reporters.
Australia should "stop making trouble in front of China's doorsteps and work with China to preserve the momentum of improving and growing China-Australia ties," she said.