The Turnbull government plans to stick with the RAAF's strict rules of engagement to avoid civilian casualties from its bombing raids in Iraq and Syria, putting it at odds with Washington's plans to ramp up the air campaign against the Islamic State group.

US Defence Secretary Ashton Carter said late last week that the US was "prepared to change the rules of engagement", referring to the tight strictures on when weapons can be released. These rules ensure air strikes are lawful and do not pose an unacceptable risk to civilians.

However, both in the US and Australia, these rules are increasingly being criticised as too tight, making it hard to hit IS targets and meaning that many missions return to base without dropping bombs.