A Sydney woman who stole a pistol from her gun club to shoot her father was found not guilty of his murder on grounds of mental illness.

Justice Peter Hall on Thursday ruled that Shamin Fernando, 44, should to be rehabilitated for chronic schizophrenia instead of jailed for killing her father, Vincent Fernando, on Aug. 22, 2010.

Fernando joined a pistol club, which had a form asking prospective members if they had any mental issues. Shamin ticked 'No.' She became a probationary member in July.

At the club's venue, she got to try shooting using the club's gun, which she later slid into her bag before leaving.

Members of the Sydney Pistol Club rang police at 3.12 p.m. on Aug. 22, 2010, to report the missing gun, the Daily Telegraph (AU) reported.

Fernando herself rang police just two minutes later confessing to having shot her father.

It was later heard in court that she asked her father to visit her at her Glebe home to load a computer program.

At the Supreme Court, she said:

"If I asked him to come round so I could shoot him I don't think he'd come."

Fernando told a psychiatrist she believed she was in a pseudo reality style TV show produced by her father, the Telegraph reported.

Hall found her mental illness as sufficient ground for a 'not guilty' ruling.

"Subject to the issue of mental illness, I have earlier indicated that the elements of the charge of murder have been established by the evidence in the Crown case," he said.

"On the question of the accused's mental condition at the time of the fatal incident, the evidence, in my opinion, it is clearly established that the accused does have available to her the defence of mental illness."

Hall ordered Fernando be kept in a mental health facility, which will release her once she is evaluated as mentally fit.