An Australian warplane has conducted the first air strike on Islamic State (IS) in Syria, destroying an armoured personnel carrier with a precision guided bomb.

In another major development, Australia will withdraw more than 100 troops from Iraq in what the government describes as reshaping the scope of the mission to advise and assist the Iraqi army.

Defence Minister Kevin Andrews said IS terror attacks in France, Kuwait, Tunisia, Turkey and Saudi Arabia reaffirmed that it remained a threat to all countries including Australia.

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He said the recent decision to extend RAAF air task group missions from Iraq into Syria was a logical extension of existing commitments which have seen combat aircraft conduct 408 missions since last October, dropping 515 bombs.

Few details of the first strike in Syria have been released.

The mission occurred in eastern Syria on September 14. Two RAAF F/A-18 Hornets spotted the armoured personnel carrier hidden in an IS compound, Mr Andrews said.

That information was relayed back to the Combined Air Operations Centre in Qatar by way of the RAAF Wedgetail airborne early warning and control aircraft.

CAOC authorised the attack to proceed and one Hornet dropped a single precision guided weapon.

Mr Andrews couldn’t say if there were casualties, though that was likely if there were personnel in the carrier.

The US Combined Joint Task Force in Kuwait indicated this attack was one of two near the eastern Syrian city of Al Hasakah, around 50-kilometres from the border with Iraq.

The Defence Minister confirmed the strikes. Photo: AAP

There were just three air strikes in Syria that day, compared with 15 in Iraq.

In an update to parliament, Mr Andrews said around 300 Australian and 100 New Zealand defence were involved in training the Iraqi army.

Another 200 Australian special forces advise the Iraqi Counter-Terrorism Service on combat tactics, care of casualties and dealing with improvised explosive devices.

Mr Andrews said the 200-member special forces group would be reduced to 80.

“This re-shaping allows Australia to balance its contribution between specialist advice and support to the Iraqi CTS provided by the Special Operations Task Group and the training provided to the regular Iraqi Army,” he said.

Opposition deputy leader Tanya Plibersek reaffirmed Labor’s bipartisan support for this mission but urged the government to match military support with an increased commitment to humanitarian assistance.

Greens deputy leader Scott Ludlam said new Prime Minister Malcolm Turnbull should reverse former PM Tony Abbott’s “captain’s call” and bring Australian military personnel home from Syria and Iraq.

-AAP