CLASSIFIED US Defence Department documents leaked to the WikiLeaks website this week suggest the Australian Defence Force covered up the killing of an Afghan policeman by Australian troops.

Buried among the 90,000 intelligence documents is a log entry about the killing of an Afghan man by an Australian mentoring and reconstruction taskforce (MRTF) patrol in the southern province of Oruzgan in December 2008.

The initial report says a suspected suicide bomber approached the patrol and was shot dead. The report was amended later in the day to show the man was a policeman, was not carrying explosives of any kind and that he was twice ordered to stop before he was shot. The Chief of the Defence Force, Angus Houston, said in a statement five months later that the man had a ''suspicious wire leading across his body'', and he was ordered twice through an interpreter to stop.

But Air Chief Marshal Houston did not disclose in the statement that the man was a police officer, or that he was not carrying explosives.