Iraqi Prime Minister Haider al-Abadi on Sunday asked Australian counterpart Tony Abott to step up military assistance to aid Baghdad's fight against the Islamic State jihadist group.

Australia is part of a US-led coalition carrying out air strikes against IS, which spearheaded an offensive that overrun swathes of Iraq, and has also deployed special forces to assist Iraqi troops.

Abbot visited Baghdad on Sunday to discuss bilateral cooperation between the two countries.

Abadi "called on the Australian side to increase the arming and speed up the training and distribution of what is needed by the Iraqi forces to decide the battle and eliminate the (IS) organisation," his office said.

The IS-led offensive in Iraq began last June, and the group's rapid expansion and brutality in areas it controls in Iraq and neighbouring Syria eventually sparked an international campaign against it.

Australia was one of the first countries to confirm its support for the US-led campaign of air strikes against IS.

Dozens of Australians are fighting for Islamic militant groups overseas, raising fears that they could return home and carry out attacks.