Japan's Ambassador to Canberra has backed Australia's demand that China's navy explains why it shined a laser at an Australian Defence force plane in the Arafura Sea, labelling it a "very dangerous" provocation.
The incident has sparked a fresh bout of recriminations between Australia and China, with Prime Minister Scott Morrison labelling it an "act of intimidation" which put the lives of the Australian air crew at risk.
Beijing has not denied that its ship lasered the Australian surveillance plane, but China's Foreign Ministry accused Australia of "maliciously spreading disinformation" about the event.
China's Defence Ministry weighed in as well, saying that the Australian aircraft dropped portable sonar systems called sonobuoys into the water near its ships in a "provocative" move.
The Defence Ministry also said the plane had come within four kilometres of the Chinese ships. But independent military analysts told the ABC that is not unusually close for surveillance planes, and could not be cast as an aggressive act.
An Australian Defence spokesperson said at the time of the incident, the closest the RAAF plane flew to the ship was 3,900 metres.
"This is a standard flight profile for Royal Australian Air Force maritime patrol aircraft for a visual inspection of a surface vessel," they said.
Japanese ambassador Yamagami Shingo said Tokyo shared Australia's concerns about what happened off the coast of the Northern Territory and said his country was "fully behind Australia on this matter".
"I think anyone who has been involved in defence or national security issues will easily agree … that this is a provocation [and] very dangerous," Ambassador Yamagami told the Australian Institute of International Affairs in Melbourne.
The ambassador said China had also targeted Japanese ships with lasers in the disputed waters of the East China Sea, where Beijing is intent on challenging Tokyo's hold on the uninhabited Senkaku island chain.
But he also stressed that while it was important to respond "firmly" to provocations, the Japanese Self Defence Force navy was also very careful not to "react in an emotional manner."
For example, if Chinese coastguard ships approached into contested waters claimed by Japan, then Tokyo would be careful not to ratchet up tensions by sending in heavily-armed naval vessels into the same area.
"This is our way of handling the matter in a professional manner without escalating the matter," he said.
The ambassador's comments are one of the first public expressions of support that Australia has received from other countries in the region since the confrontation.
On Monday, the Prime Minister said Australia was demanding an explanation from China on behalf of several other countries in the region who were also worried about aggressive behaviour by China's navy.
"We expect, and not just Australia, [but] all countries in the region demand an answer to this because it's an Australian surveillance aircraft this time — [but] who's next?" Mr Morrison told reporters.
But so far most major countries in the immediate region – including Indonesia and Papua New Guinea – have steered well clear of the controversy and have made no public remark about what happened.
Ambassador Yamagami said he believed the behaviour of China's navy was "constantly discussed" by the four Quad countries – Australia, India, the United States and Japan – and was likely to be a focus of the AUKUS defence agreement as well.
He also predicted that a "number of like-minded" countries would support Australia in any dispute with China over the matter, although he didn't predict what form that support might take.
