The Australian government on Monday banned its citizens from travelling to Mosul in northern Iraq without a "legitimate" reason.
Mosul district, in Nineveh province, is the largest city in Iraq controlled by the Islamic State (IS) terror group since June last year.
Foreign Minister Julie Bishop said anyone entering or remaining in Mosul would face up to 10 years in jail, ABC reported.
"The government is determined to stop Australians joining the terrorist conflict in Iraq and Syria and supporting terrorist organisations," Bishop said in a statement.
"Advice from Australia's security and intelligence agencies, and those of our international partners clearly indicate that IS is engaged in hostile activities in the district of Mosul."
She said the terror group had committed barbaric acts in Mosul, including mass public executions and beheadings, and that the destruction of ancient artefacts was also of great concern.
IS militants were recently shown in videos using sledgehammers and power drills to destroy 3,000-year-old sculptures and statues in Mosul.
"It was reminiscent of the Taliban's destruction of ancient Buddhist statues in Afghanistan in 2001," Bishop said.
Monday's announcement is the second time Australia has used a tough new law barring overseas travel to specific areas, following a ban on the province of Al-Raqqa in Syria, a key strategic hub for IS militants.
In September, the UN demanded that all countries make it a serious criminal offence for citizens to travel abroad to fight with militant groups, or recruit and fund others to do so.
