An Australian man claiming to be a doctor has appeared in an Islamic State propaganda video urging other health professionals to join the group's new health service.

The video, published on Friday, has not been verified but has been circulated by IS-linked social media accounts.

It shows a young doctor calling himself Abu Yusuf explain that he travelled from Australia to the IS stronghold of Raqqa, in Syria, to live under the caliphate and use his medical skills to help others.