Australian Prime Minister Malcolm Turnbull will link security and economic prosperity in a key speech at the ASEAN-Australia summit on Saturday, as Canberra looks to bolster the group and expand its role in the region.

Nine of the 10 leaders from the Association of South-East Asian Nations are in Sydney for a special summit with Australia. The meeting comes at a time of great uncertainty in the region as the US adopts an America-first approach to foreign policy and Chinese President Xi Jinping seeks to extend his time in power.