The Australian Defence Force says reports it killed civilians during airstrikes in Iraq in 2017 are "credible".

Chief of Joint Operations Air Marshal Mel Hupfeld said Australian Super Hornets "may have" killed an estimated six to 18 civilians at the height of the battle to defeat Islamic State in Mosul in 2017.

According to the ADF, Iraqi security forces requested help on June 13, 2017, after Islamic State fighters were spotted setting up positions in a built-up west Mosul neighbourhood. As part of the response from the US-led international coalition, two Australian Super Hornets dropped bombs on a building and a courtyard.

Air Marshal Mel Hupfeld says reports Australian airstrikes killed civilians in Iraq are credible.

The ADF says its air crews hit the targets accurately and initial Australian assessments suggested there were no civilian casualties. But Airwars - a website that tracks civilian deaths in war - claimed civilians in a nearby building were killed.