An ISIS bride who was barred from returning to Australia has 'disappeared into a Syrian prison system' notorious for torturing its inmates.

Last month, Hodan Abby and her young disabled daughter attempted to board a flight from Damascus to Sydney with others linked to the terrorist group.

She was denied boarding after reportedly receiving a government-issued temporary exclusion order months prior.

Abby, 29, was given the option of allowing her nine-year-old daughter to return to Australia with the other mothers, but she declined.

Syrian authorities sent the pair to a prison in Idlib, a small city in Syria's northwest, where Abby has no means of contacting her family, The Australian reports.

While it is not known what prison Abby and her daughter have been housed in, conditions in Idlib facilities are known to be dire.

In 2012, the Human Rights Watch said Idlib prisons, some of which are controlled by Sunni Islamist extremist group HTS, are known for their rampant torture, medical negligence and overcrowding.

'Almost all former detainees interviewed by HRW said they had been subjected to torture or witnessed the torture of others during their detention,' HRW said.

'Interrogators, guards and officers used a broad range of torture methods, including prolonged beatings, often with objects such as batons and cables, holding detainees in painful stress positions for prolonged periods of time, the use of electricity, burning with acid, sexual assault and humiliation, the pulling of fingernails, and mock execution.'

The most notorious detention centre in Idlib is the Oqab Prison, where widespread torture has been documented. It is possible Abby is being held there.

After fleeing her western Sydney home with a friend at the age of 18, Abby spent years trapped in Kurdish-run camps with her daughter, who suffered shrapnel wounds to her head, hip and back.

The girl lives with disabilities and ongoing speech and movement impairments as a result of her injuries.

Abby is believed to have last been in contact with her family around three weeks ago, where she told them she was 'OK' after being turned away at Damascus airport.

Her relatives then engaged Birchgrove Legal principal solicitor Moustafa Kheir, hoping to challenge the federal government-issued exclusion order.

'The family has lost total contact with their daughter,' a source told The Australian.

'They are worried about her safety and that's the only driving factor at the moment. It's the only thing on their minds.

'The lawyer (Mr Kheir) is in the same boat. There's no information coming from Hodan so they can't seek instructions, they can't progress anything at the moment.'

News of Abby's imprisonment comes just days after an ISIS handbook that gave men a green light to capture and rape slaves was revealed in a Melbourne court last week.

The pamphlet was mentioned during a hearing for ISIS bride Zeinab Ahmad, 31, who is facing two counts of crimes against humanity, including enslavement and using a slave, which was allegedly authorised by the handbook.

'The Islamic State Office of Research and Fatwas published the pamphlet "Su’al wa-Jawab fi al-Sabi wa-Riqab" [Questions and Answers on Taking Captives and Slaves],' Detective Senior Constable Marc Clendenning told the court.

'[It] states that it is permissible to rape female captives, to sell, purchase, gift or trade slaves, and outlines instructions around the sexual abuse of slaves.

'The Q&A also provides for the physical punishment of female captives as a “form of discipline” within certain limits.'

Australian authorities allege Ahmad was more than just a witness to the torment and abuse of slaves, but was an active participant after her family bought the girl, who cannot be named for legal reasons, for US$10,000 during Ramadan in 2017.

'The accused was in charge of everything if her parents were not in the house. She was like a deputy,' the detective told the court. 

The girl had allegedly been taken captive as a 15-year-old when ISIS combatants murdered her mother and brother.

Over the next five years she was said to have been traded about 17 times to different ISIS members, who beat, tortured and raped her.

Ahmad is expected to front Melbourne Magistrates Court on Monday where her bail application continues.