The Australian Federal Police have issued an arrest warrant for Toowoomba teenager Oliver Bridgeman.
Mr Bridgeman has been in Syria since May, 2015 where he says he has been doing aid work.
In a statement provided to SBS News, the AFP said the arrest warrant related to alleged breaches of Australia's terrorism laws, which prohibit citizens from fighting in foreign countries.
"As this matter is ongoing, and yet to be tested before a court, it would not be appropriate for the AFP to comment further," the statement said.
Mr Bridgeman's legal team said the allegations involved his intentions when he entered Syria one year ago.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
"Despite presumably having all relevant evidence for 12 months, the AFP has chosen to only now issue a warrant - a matter of days after the filing of an appeal to have Mr Bridgeman's passport returned, so he could come home," the law firm said in a statement.
The AFP had at all times asserted that they only wanted Mr Bridgeman to return to Australia, they added.
"It seems the government is doing everything possible to ensure Mr Bridgeman remains stranded in Syria," the statement said.
"Without government intervention, it is highly likely he would already be home."
Mr Bridgeman has indicated a willingness to co-operate with authorities.
Mr Bridgeman's passport was recently cancelled and his lawyers have been working to have the decision overturned.
On Wednesday the Guardian Australia reported the AFP's case against Mr Bridgeman was based on social media posts he had made and several print and broadcast media reports.
- with AAP
