Former prime minister Tony Abbott believes the deadly Paris terrorist attacks and other recent bombings show the "vicious and evil" Islamic State is getting stronger.
Mr Abbott told Network Ten on Sunday Islamic State must be defeated abroad and called on governments to continue supporting security agencies and reaching out to Muslims who find the attacks abhorrent.
But he was encouraged by statements by "respectable, humane Muslim leaders" like Egyptian president Abdel Fattah el-Sisi, calling for a revolution of Islam to overcome "centuries of false thinking".
But Mr Abbott said the latest atrocity showed allied forces needed to do more to tackle IS in Syria and Iraq.
"It has to be defeated and it's not going to go away just by wishing it to go away," he said.
"It's only going to be defeated if people take very strong steps against it."
He hoped the latest attacks would strengthen the western world's resolve but refused to be drawn on whether Australian troops should be sent into ground combat in the Middle East.
