The woman has brought the personal injury suit in the ACT Supreme Court and is claiming tens of thousands of dollars for medical fees, but will also claim for future financial losses.

The woman purchased a unit in Geocon's Observatory Living development in Wright in 2015.

She is suing the construction arm of Geocon and the sales arm of the business for both building and then selling an allegedly defective home.

The claim further alleges that Geocon failed to take any steps to identify the cause of harm to the woman and failed to take any steps to fix the unit after she had raised the issues.

Geocon has filed a defence with the court denying all negligence and has tried to shift blame to a subcontractor, who completed the waterproofing of the unit, claiming any negligence would be the subcontractor's fault.

The woman claims that due to the defective unit she was exposed to mould which caused a significant number of illnesses and disabilities.

She says she contracted Hashimoto's disease, coeliac disease, pyrroluria, costochondritis and possibly Mast Cell Activation Syndrome, among other illnesses.

The diseases cover immune disorders, issues with thyroid function, mental health concerns, skin conditions and various joint and muscle inflammation.

The woman also allegedly suffered from nausea, fevers, memory loss, swelling and stiffness in her joints, depression and anxiety; all allegedly caused by the mould and associated stress of the defective unit.

Accompanying her claim is an extensive list of medical experts who have treated her.

Court documents contain a table of costs for medical expenses to September last year which totalled more than $23,000. One of the woman's treating physicians estimated her medical costs in the next three years at more than $31,000.

The woman is also claiming for economic loss for time off work due to illness and medical appointments. Her lawyers are yet to file the exact figure of estimated future losses that will be claimed.

In Geocon's filed defence, the company denies it was negligent, denies it breached its contract with the woman and denies it breached its statutory duty.

Geocon does not admit that the woman suffered any injuries or disabilities and if it is found she did, the company says those were not caused by any negligence by Geocon.

Lawyers for Geocon have filed a third-party notice against Flora & H Pty Ltd, which Geocon says it contracted to provide waterproofing work at the Observatory Living development.

This means should Geocon be found liable towards the woman by the court, it will claim indemnity or a contribution from the subcontractor.

Geocon says the subcontractor owed the woman a duty of care in conducting its waterproofing and breached that duty.

Geocon has previously settled a lawsuit brought by the same woman regarding the allegedly defective home. Documents from that case highlighted claims of excessive amounts of mould within the unit and contained an engineering consultant's report which described the home as "uninhabitable".

Recognition of illnesses caused by mould exposure has grown in recent years. A federal parliamentary inquiry into biotoxin-related illnesses found last year that although there is not yet consensus, the medical evidence pointed to some individuals being susceptible to serious illness due to mould.

The suit will return to court next week for directions and possible mediation.