Australian and American defence leaders have refused to say whether coalition soldiers were with Iraqi forces on the streets of Mosul when they were caught in a chemical attack by Islamic State extremists.
Defence Minister Marise Payne said Australian troops worked with Iraqis every day as part of their advise-and-assist mission.
When troops were deployed to Iraq two years ago, then-defence minister Kevin Andrews promised their mission would be entirely "behind the wire" of the Taji training base near Baghdad.
There would be no combat involvement, he insisted.
In mid-2016 some small groups of trainers ventured out to secure coalition facilities where they instructed Iraqi soldiers in use of larger weapons such as mortars.
While Defence told the ABC that Australian and US advisers were with the Iraqi unit in west Mosul at the time of Saturday's attack, Senator Payne has refused to provide location details.
"I'm actually not going to detail the physical location of Australian troops in a conflict zone in the Middle East," she told ABC radio on Thursday.
"No Australian personnel were exposed during the gas attack on those Iraqi ground forces in Mosul.
"What the Australian forces did in this context was Australian medics at a secure base which is outside Mosul provided first aid to those Iraqi soldiers who were affected by the gas attack."
The head of ground forces for the US-led coalition in Iraq, Major General Joseph Martin, told reporters American advisers were with Iraqi security forces at command and control locations throughout Iraq.
He shied away from repeated direct questions about Australians and Americans being on the ground during the chemical attack.
"We're forward with the Iraqis each and every day and with that, we share some risk with them," General Martin said, while refusing to go into detail about the chemical attack.
"And so, with that risk, there's danger. But our soldiers are prepared with the appropriate equipment and they have the training necessary to defend against that."
The US is testing the chemical used to work out what it was, but expects the weapon would have been low-grade based on past experience.