"The Australian Government has sought an explanation from China", a Department of Foreign Affairs spokesperson told AFP, signalling unease at the launch, which appeared to be linked to the modernisation of Beijing's nuclear triad of air, land and sea-based weapons.

"Australia is concerned by any action that is destabilising and raises the risk of miscalculation in the region, and is consulting regional partners about this launch," the official said.

Beijing first test-fired an ICBM into the South Pacific in the 1980s but has since conducted tests in its own airspace.

The test was always likely to bring condemnation from Washington's allies in the region, but the response from smaller Pacific Island nations will also be closely watched.

The United States and China have been vying for influence across the South Pacific, opening embassies, inking agreements and doling out cash for projects.

The region is home to vast ocean resources and encompasses several vital trade routes.

Pacific nations are keen to profit from US-China competition but want to avoid the region becoming militarised.

Japan and New Zealand have already decried the test, which China's military said was "routine".

The Australian spokesperson said, "the launch comes in the context of China's rapid military build-up, which is taking place without the transparency and reassurance that the region looks for from great powers".