Yinou "Ginger" Jiang and her friend Pingkang "Connie" Zhang were inside a fifth-floor apartment at the West Terrace development in Bankstown on September 6, 2012, when a fire started on the balcony and quickly spread inside.

The pair became trapped in a bedroom and climbed onto the narrow window ledge outside, but the fire's heat was so unbearable they were forced to jump.

Ms Zhang - a promising pharmacy and nursing student - died, while Ms Jiang survived with "severe injuries" to her legs that require her to use a wheelchair.

Ms Jiang and her parents are now seeking damages, interest and costs in the Supreme Court, as are Ms Zhang's parents and the student's boyfriend Shengkai Li.

According to court documents, Ms Zhang phoned her boyfriend multiple times as the blaze consumed the apartment, but the calls were interrupted by poor reception. When Mr Li rushed home, he discovered she had died.

The families are suing the apartment's landlord, James Peng; the Property Investor Alliance, which allegedly told Mr Peng he could build another bedroom in the unit; and the company responsible for installing extinguishers in the building.

They are also suing the body corporate, the realty group that managed the building, the certifier who issued an occupancy certificate for the building and Silky Constructions, who built the apartments.

They allege fire risks at the apartment were "forseeable" and "not insignificant", and all defendants were under a duty to take precautions against the risk of harm.

In documents lodged with the Supreme Court, Ms Jiang and the other plaintiffs allege an extra room was added inside the apartment without appropriate or qualified advice, so it could be rented out to more people to make more money.

This added "additional fuel", made the unit "more of a fire risk", and allegedly made it harder to escape.

It is further alleged the builders modified the building's plans without council approval, to "shav[e] centimetres off the building's height" so it would be just shy of 25 metres tall, the threshold at which a sprinkler system must be installed.

It is alleged the defendants breached their duty of care by failing to install fire sprinklers, failing to ensure fire doors were working, and issuing the occupancy certificate for the building when it did not have sprinklers.

In court documents, Ms Jiang, Mr Li and the parents of both women say they suffered damage as a result of the fire.

Ms Jiang's parents suffered "injury, loss and damage" upon hearing of her injuries, while Ms Zhang's parents suffered "injury" and distress when they were told of their daughter's death.

In a statement of claim, Ms Zhang's mother says she suffers depression, anxiety, PTSD, nightmares and flashbacks as a result of what her daughter went through.

Ms Zhang attended the University of Sydney on a scholarship and would have completed her combined degree by the end of 2017 if she had not died, her parents said. She would then have been able to support them.

The claims are being defended on several counts, with the defendants denying some of the allegations against them, denying they had a duty of care, and saying the action should be "statute barred" because it has been brought more than three years after the fire.

The body corporate is also suing the apartment's builders and developers, seeking costs to rectify "defects" in the apartment block.

The matter will return to court next year.