Australia plane had 'right' to watch China navy vessel in its waters: PM Morrison

China's defence ministry on Monday said the surveillance plane had dropped a sonobuoy, which can help detect submarines, near the Chinese ships, and had flown as close as 4km from the convoy, which it said was "provocative and dangerous".

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

Morrison said the surveillance plane's crew "were doing their job", and repeated his demand for an explanation from Beijing.

On Tuesday, Morrison announced separately Australia would spend A$804 million (US$578 million) to buy drones and helicopters and set up mobile stations in Antarctica, because Australia needed to "keep watch" on the region.

He said that China did not share Australia's objectives in Antarctica, 42per cent of which is claimed by Australia, and that Beijing wanted to exploit its resources.

"We need to keep eyes in Antarctica because there are others who have different objectives to us, and we need to make sure not just for Australia's interest, but for the world's interest, that we protect this incredible environment that we have responsibility for," he said.