Three sisters who were suing former politician Kristina Keneally for torture have had their case thrown out.

Sandra, Jessica and Michelle Lazarus sued the former NSW premier over a 2010 corruption investigation she authorised, which they say caused them “mental anguish”.

The Independent Commission Against Corruption was investigating claims about financial fraud at the Royal Hospital for Women and the Royal North Shore Hospital in Sydney.

The watchdog found Sandra Lazarus had falsely presented herself to hospitals as a PhD student from the University of Sydney.

Using her position, she and Michelle had forged the signatures of doctors and filed invoices for goods and services that never existed or were never delivered from 2007 to 2009, claiming payments of more than $680,000.

In 2014, Michelle was found guilty of lying to the commission and received a suspended sentence of nine months while Jessica was not charged.

A year later, Sandra was sentenced to one year and nine months in prison after being found guilty for fraud.

The three sisters have denied any wrongdoing and claim the commission had acted outside its jurisdiction.

They also alleged they suffered mental anguish as a result and are suing Ms Keneally for authorising the ICAC investigation during her term as NSW premier.

On their website, they claim their lives were threatened by the government, and that they suffered physical and mental abuse at the hands of ICAC officials.

In their Supreme Court case, the sisters attempted to sue Ms Keneally, Magistrate Joanne Keogh who presided over their criminal trials, the NSW Crime Commissioner Michael Barnes and Supreme Court judge Peter Garling.

The sisters claimed the defendants “tortured” them as they underwent the ICAC investigation and their own trials.

They also alleged Ms Keogh’s conviction of Sandra led her to be placed into custody, which exacerbated her permanent spinal injury and requested all their convictions be quashed.

But in November, the sisters attempted to discontinue their case, which Ms Keneally’s solicitors did not consent to.

On Tuesday Justice Mark Ierace refused leave and instead dismissed the case, ordering Michelle and Sandra to pay the attorney-general’s costs of the proceedings.

Neither the litigants nor Ms Keneally attended the Supreme Court.

Previously, the sisters have unsuccessfully sued ICAC, the Northern Sydney and South Eastern Sydney Local Health Districts, the Director of Public Prosecutions, the State of NSW, and the Local Court of NSW.