One of the victims of Australia's Lindt Cafe stand-off was reportedly killed by a police bullet when she was caught in the crossfire between the gunman and the cops, media report said today.

Katrina Dawson, 38, was caught in the crossfire and struck possibly by a ricochet. "The barrister was struck by police fire that was not a direct shot and possibly a ricochet, when tactical operations unit officers stormed the cafe just after 2am on 16 December," police was quoted as saying by Sydney Morning Herald.

Iranian-born Islamic State sympathiser Man Haron Monis had shot dead one of the hostages, cafe manager Tori Johnson, at close range. Monis was later killed in the shoot-out with police.

"Force would not be commenting on any aspect of the investigation until that process had been completed," a police spokeswoman said. Dawson and Johnson, 34, were among the 18 hostages detained by Monis when the Martin Place siege began just before 10am.