A Saudi woman who says she is fleeing abuse by her family and wants asylum in Australia has barricaded herself in an airport hotel room at an international airport in the Thai capital and is sending out desperate pleas for help over social media.

Rahaf Mohammed Alqunun began posting on Twitter late Saturday after her passport was taken away when she arrived on a flight from Kuwait. The 18-year-old has been appealing for aid from the United Nations refugee agency and anyone else who can help.

On Twitter, she wrote of being in "real danger" if forced to return to her family under pressure from Saudi authorities. She tweeted Monday that a friend would carry on posting to her account if she was taken away or denied access to it.