UNITED Arab Emirate authorities have locked up an Adelaide man without charge because he shared a Facebook post supporting a refugee charity.

Scott Richards was arrested three weeks ago after he breached UAE regulations that say people in the country cannot promote overseas charities, the ABC reports.

Mr Richards' family is urging the Australian government to work with the UAE government to get the detainee released.

His family says the Zwan Family Charity volunteer has not seen a lawyer since being locked up in the Al Murraqabat Police Station in July.

The charity gives tarpaulins to people living in Afghanistan refugee camps.

Mr Richards' mother Penelope Haberfeld said her son saw his wife once a week and could only make a few phone calls.

"It's the indefinite detention, it can go on for months, years," she told the ABC.

The charity described Mr Richards as  "friend of a supporter".

The  Department of Foreign Affairs and Trade told the ABC it knew an  Australian-UK dual national was being held in the United Arab Emirates.

"As the man is a resident in the UAE on his UK passport, he is receiving consular assistance from the UK Embassy," a DFAT spokesman said.

"The Australian Consulate-General is in contact with the UK Embassy to monitor developments in the case." - ARM NEWSDESK