Australian special forces could get the green light to enter Iraq within days to commence their long-planned "advise and assist" mission with Iraqi forces now that the main impediment has been resolved through the appointment of an Iraqi defence minister.

The absence of a defence minister had been described as the major hold-up resulting in up to 200 special forces commandos cooling their heels in the United Arab Emirates, even as the air campaign proceeded.

The crucial development means a status of forces agreement between Canberra and Baghdad can now be signed providing legal powers and indemnities for Australian special forces who will in some cases operate in the field with local combat units.

It came as Foreign Affairs Minister Julie Bishop used a lightning secret visit to Baghdad to reaffirm Australia's opposition to putting conventional ground troops directly in the battlefield to fight Islamic militants in Iraq.

After months of paralysis, the Iraqi parliament has approved the appointment of the last two cabinet ministers to what is supposed to be an inclusive national unity government, installing a Sunni Muslim in the defence ministry and a Shia Muslim as interior minister.

The appointment of Khaled al-Obeidi, a Sunni, is seen as particularly significant given the Iraqi fight with the Islamic State Sunni extremist group.

Speaking at a joint press conference on Saturday with her Iraqi counterpart, Ibrahim al-Jaafari, Ms Bishop said Australia would only provide assistance "at the invitation of and with the consent of the Iraqi government".

"From Australia's perspective we do not envisage sending ground forces. We have not been asked to, we have not offered to, so we do not envisage that being part of our arrangement with Iraq," Ms Bishop said.

Australia has taken part in air strikes against Islamic State targets in Iraq but is still awaiting legal agreement with the new Iraqi government over the deployment of 200 special forces trainers.

Dr al-Jaafari said the Iraqi government had never asked for foreign ground forces and would not make such a request in the future.

"We consider ground troops from other countries entering Iraq is a red line, because we do not want to put anyone or any country in danger by fighting in our lands," Dr al-Jaafari said.

Dr al-Jaafari thanked Australia for the military and financial assistance it was providing to his country and said he and Ms Bishop had discussed how Australia could assist Iraq "politically and economically".

Ms Bishop said Australia was determined to play its part to assist Iraq in its fight against Islamic State, which she said "poses not only a threat to Iraq but to the region and globally".

Ms Bishop is scheduled to meet Iraqi President Fouad Massoum and the Speaker of the Iraqi parliament, Salim al-Jabouri, on Sunday before departing for Canberra, where Parliament will sit on Monday.