Beijing: China's support for tougher sanctions against North Korea has been prompted in part by concerns of an evolving US-anchored missile defence system on its borders, say Chinese and Western analysts.

The missile defence systems involve new land- and sea-based radar systems, missile interceptors and intelligence sharing between the US and its regional allies which is aimed at shooting down a North Korean missile during the relatively low-velocity launch phase.

Analysts note that these systems could also be used to shoot down missiles launched from China's eastern regions.

Australia is building three air warfare destroyers with AEGIS radar and missile control systems that can be potentially integrated into the US system.