Australian anti-Islamic State (IS) fighter Ashley Dyball says he has been charged as a terrorist and will be deported from Germany to Australia.

Dyball, from Brisbane, has posted on social media saying he is being sent to the Eisenhüttenstadt Detention Centre and will be on a flight back to Australia in two days' time.

"If anyone has a good german [sic] lawyer help a brother out been charged as a terrorist," he wrote on Facebook, under his alias Mitchell Scott.

The 23-year-old has been fighting against IS forces with a Kurdish militia called the YPG in northern Syria, but was apparently travelling through Europe during a break from the battlefield when he was detained.

His family wants the Federal Government to grant an amnesty under the tough foreign fighters legislation to those battling the Islamic State group.

A spokesperson for the Department of Foreign Affairs and Trade said it was providing consular assistance "to an Australian man detained in Germany".

"Due to privacy constraints, we will not comment further."