Sydney - Australian Prime Minister Scott Morrison defended an Australian surveillance plane and said it was doing its job when it was "put under threat" with a laser from a Chinese navy ship, rejecting Beijing's statement that the plane came too close.

The P-8A Poseidon - a maritime patrol aircraft - detected a laser emanating from a People's Liberation Army Navy (PLAN) vessel last Thursday. Australia had also released photographs of two Chinese vessels sailing close to its north coast.

Australia's department of defence said on Tuesday that the aircraft dropped sonobuoys after the lasing incident, also quoting that the surveillance devices aren't a shipping hazard.

The Chinese guided missile destroyer and an amphibious transport dock were sailing east through the Arafura Sea between New Guinea and Australia, and later passed through the narrow Torres Strait, Australia's defence department says.

Beijing says the Chinese ships had a legal right to be in international waters, which Australia has not disputed. The defence ministry also said on Monday that the surveillance plane had dropped a sonobuoy, which can help detect submarines, near the Chinese ships, and had flown as close as 4km (2.5 miles) from the convoy. The ministry said the move was "provocative and dangerous".

"No sonobuoys were used prior to the PLA-N vessel directing its laser at the P-8A aircraft on 17 February. Some sonobuoys were used after the incident but were dropped in the water a significant distance ahead of the PLA-N vessel," Australia's department of defence said.

The devices "collect passive acoustic data" on ships and submarines, it said.

The aircraft was 7.7km from the Chinese naval vessel at the time of the lasing incident, it said, and the closest it flew was 3.9km, which Australia said was standard for a visual inspection of a vessel.

Morrison also said that China did not share Australia’s objectives in Antarctica, 42% of which is claimed by Australia, and that Beijing wanted to exploit its resources.
-Reuters