CANBERRA, Nov. 24 -- Australia's Prime Minister Malcolm Turnbull warned Tuesday that a terrorist attack on Australian soil is "likely" at some stage in the future, and Australians need to be aware of that possibility.

Turnbull, in his first national security address to the parliament, said the Islamic State (IS) group had been weakened by recent air strikes and now had "many more smartphones than guns, many more Twitter accounts than soldiers."

"By most measures, however, ISIL (another name for IS) is in a fundamentally weak position. It does not command broad-based legitimacy even in those areas under its direct control. It is encircled by hostile forces. It is under military pressure."

Turnbull, who has just returned from an overseas trip in which he met world leaders at the G20 summit, APEC and the East Asia summit, said Australia would continue with its air strikes against IS strongholds in Syria and Iraq, but had no plans to commit troops to the region.

However, if the government received a request from its allies - including the United States and Britain, presumably - the prime minister said it would "carefully" reconsider its position.