Australian forces are expected to get the go-ahead today to join air strikes on Islamic State (IS) militants in Iraq.

The ABC has been told the National Security Committee of Cabinet is meeting this morning to clear the plans for the US-led fight.

Defence Force Chief Mark Binskin has arrived at Parliament House for the meeting.

The decision will only involve the RAAF Super Hornet jets and not the use of special forces troops.

National Security Committee of Cabinet members The National Security Committee (NSC) focuses on major international security issues of strategic importance to Australia. Decisions of the NSC do not require the endorsement of the Cabinet. Chair Tony Abbott - Prime Minister Deputy Chair Warren Truss - Deputy Prime Minister Members Julie Bishop - Minister for Foreign Affairs George Brandis - Attorney-General Joe Hockey - Federal Treasurer David Johnston - Minister for Defence Scott Morrison - Minister for Immigration and Border Protection Member Co-optee as required Mathias Corman - Minister for Finance Source: Commonwealth Parliament

Australian planes have been flying reconnaissance missions over Iraq this week as part of the international coalition, but the Government has been waiting on diplomatic clearances from the Iraq government before it launched any attacks.

The clearance means that the planes could join combat missions once approval is given by the Iraq government.

After the National Security Committee of Cabinet meeting, the government will hold a full Cabinet meeting before briefing Opposition Leader Bill Shorten and then releasing a public statement.

On Thursday Australian refuelling and surveillance planes flew their first mission over Iraq in support of the international coalition.

Ahead of those flights Prime Minister Tony Abbott said Australia's mission was "support operations, not strike missions".

"Australian air strikes await final clearances from the Iraqi government and a further decision by our own. But from today our refueller and our Wedgetail [surveillance aircraft] will operate over Iraq in support of US and other coalition aircraft," he said.

Australia last month sent 600 military personnel and eight F/A-18F Super Hornet fighter jets to the United Arab Emirates in preparation for joining the attack on IS targets in Iraq.

Retired major-general Jim Molan, who was the chief of operations for 300,000 coalition troops in Iraq in 2004, said the campaign against IS was likely to run for a long time.

"Air strikes will be effective because the people who are running it have extraordinary experience first of using air power where it's relevant, and secondly of working air power in with troops on the ground," he told ABC News Breakfast .

"People are saying you can't win this war with air strikes and I have never met anyone who said we could.

"It's going to take Australia a long time, I think to get the Iraqi military and the Kurds and of course within Syria which is not our game at this stage, to get them up and to get them fighting again.

"So yes, we might quickly do strikes but this is a campaign which will run for a long time and it's nowhere near its peak."

Major-general Molan said he sees special forces troops "working with and training and advising and mentoring local combat forces".

Sorry, this video has expired Jim Molan says the campaign against IS will 'run for a long time'.

"That seems to be what the Government is saying at the moment."

Government frontbencher Malcolm Turnbull has told Channel Nine while Australia has said it will not send in troops on the ground, that may change.

"You can't rule anything out - and if anyone was going to make a forecast like that it should be the Prime Minister," he said.

"But clearly foreign interventions in that part of the world have had - let's say most generously - mixed success. Not a lot of success."