An 18-year-old Saudi woman seeking asylum has left Bangkok airport "under the care" of the UN refugee agency, a Thai official said, following her plea against deportation.

"She is allowed to stay ... she is under the care of the UNHCR now," said immigration chief Surachate Hakparn.

"She left the airport with the UNHCR." 

Earlier, Thai immigration officials said that Rahaf Mohammed al-Qunun would not be forcibly deported after a Thai court dismissed an injunction request to prevent her deportation.

The injunction was filed at Bangkok's Criminal Court to prevent Ms Qunun from being returned to Saudi Arabia.

She said she was fleeing her "abusive" family while travelling in Kuwait, and had flown to Thailand in the hope of reaching Australia to seek asylum. 

But she was stopped yesterday when she got off the plane in Bangkok's Suvarnabhumi airport by Kuwaiti and Saudi embassy officials, she said, and has since been held in an airport hotel awaiting deportation.

Ms Qunun told AFP she feared that she would be killed if she is returned to Saudi Arabia.

She had reportedly barricaded herself inside a Thai airport hotel, refusing to allow immigration officials to escort her on to a flight to Kuwait and said she fears her family will kill her.

The Saudi Foreign Ministry denied her allegations that its embassy had confiscated her passport, saying in a tweet that she was stopped at the airport for violating Thai immigration laws.

Ms Qunun posted a video on Twitter of her barricading her hotel door with a table and a mattress.

"My brothers and family and the Saudi embassy will be waiting for me in Kuwait," Ms Qunun said by text and voice message from the hotel yesterday.

"They will kill me," she said. "My life is in danger. My family threatens to kill me for the most trivial things."

Asked why she was seeking refuge in Australia, she said: "Physical, emotional and verbal abuse and being imprisoned inside the house for months. They threaten to kill me and prevent me from continuing my education.

"They won't let me drive or travel. I am oppressed. I love life and work and I am very ambitious but my family is preventing me from living."

Human rights lawyer Nadthasiri Bergman told AFP she filed an injunction to Bangkok's criminal court to prevent Ms Qunun's deportation.

"In the event when we suspect that someone might be illegally detained, we request for the court to call the relevant authorities (in) for questioning," said Ms Bergman.

"For now, I just called for the immigration and Rahaf herself, and the staff at the hotel" to be questioned, she added.

Ms Bergman said Thai authorities had no grounds to hold Ms Qunun if she had a passport and a visa for travel to Australia.