Australia's prime minister as he outlined tougher measures to fight the threat posed by the Islamic State movement.

Prime Minister Malcolm Turnbull told Parliament on Thursday that Australian law will soon be amended to give Australian F/A-18 Hornet fighter jet pilots the same legal standing as their coalition partners when conducting airstrikes against Islamic State targets in Iraq and Syria.

The Australian legal definition of combatants will be expanded to include people supporting armed fighters and will become consistent with international norms. The tighter Australian definition has limited the potential targets that Australian war planes can attack and has affected the timing of those attacks.