Warrants issued for Aussie jihadists

Two Australians believed to be fighting with terrorists in Syria and Iraq will be arrested if they return home.

The Australian Federal Police has issued arrest warrants for Mohamed Elomar and convicted terrorist Khaled Sharrouf.

The warrants relate to alleged terrorist activity, an AFP spokeswoman told AAP.

"Should Sharrouf or Elomar return to Australia, these warrants authorise law enforcement to arrest them immediately," she said.

The pair have reportedly joined the Islamic State (ISIS) insurgents fighting in Syria and Iraq.

Sharrouf's social media profile has shown him waving the organisation's flag.

There are also reports of photos posted online of Elomar holding the severed heads of Syrian government soldiers.

More than 100 Australians are believed to have left the country to fight in the Middle East, with dozens known to be actively involved.

ASIO has advised the Australian government that ISIS is attracting a large number of foreign fighters and is now one of the world's most deadly and active terrorist organisations.