"My unambiguous message to all Australians who fight with terrorist groups is that you will be arrested, prosecuted and jailed for a very long time," Abbott told parliament in a statement on national security.
Australia has announced tougher counter-terrorism laws to target home-grown terrorists and those who fight overseas over fears violent citizens in Syria and Iraq will return home, AFP reported.
"Our laws are being changed to make it easier to keep potential terrorists off our streets," Abbott said after the biggest security crackdown in Australian history last Thursday saw more than 800 police officers raid nearly 30 homes.
A 22-year-old man was charged with planning a terrorist act.
The government said it had foiled a plot by ISIL militants to carry out gruesome "demonstration executions" in Australia.
Abbott said 60 Australians were known to be fighting in Iraq and Syria, 20 had already returned to Australia while another 100 actively support militants.