Germany is deporting an Australian man who joined a Kurdish militia group to fight the Islamic State (IS) group in Iraq and Syria, Sydney's Foreign Ministry has said.

Australian media had reported that Ashley Dyball was detained in Germany after travelling to Europe for a break from fighting with a Kurdish group known as YPG.

Dyball, who also uses the alias Mitchell Scott, posted on Facebook on December 4 that he had been charged as a terrorist and was being sent to the Eisenhuettenstadt Detention Center near the German border with Poland.

He said he will be deported to Australia on December 6.

The Brisbane man has been fighting against IS since early 2015. Two other Australians have been killed fighting with YPG this year.

It is not clear whether Dyball will be subject to penalties under Australian laws designed to punish people who fought with IS, rather than those who fought against the militant group.

Based on reporting by AFP and dpa