A former Australian soldier has been arrested over allegations of war crimes in Afghanistan, police said on Tuesday.

Police declined to name the man, however local media reported he is one of the country's highest decorated former soldiers, Ben Roberts-Smith.

Roberts-Smith was awarded Australia's highest award, the Victoria Cross, for his bravery during a 2010 battle against Taliban fighters in Kandahar, Afghanistan.

On Tuesday, Australian Federal Police (AFP) said a former Australian Defence Force member, aged 47, had been arrested after a joint investigation between the Office of the Special Investigator (OSI) and the AFP.

AFP said the man was arrested at Sydney Domestic Airport and is expected to be charged with five counts of war crimes involving murder.

The allegations include that he intentionally caused the death of two people in Afghanistan between April 2009 and October 2012.

He is also accused of aiding, abetting, counselling or procuring another person to intentionally cause the death of a person on three separate occasions.

Police said the maximum penalty for the offence of war crime - murder is life imprisonment.

The joint OSI-AFP investigation began in 2021, and inquiries are continuing, police said.

OSI director of investigations Ross Barnett told media the case was one of 53 investigations involving allegations of war crimes by Australian Defence Force members in Afghanistan.

In total, 39 of those have been finalized with no charges and 10 are ongoing. One other investigation has resulted in a former solider being charged with one count of war crime – murder. That trial is due to take place in February.