Already referred to the NSW Judicial Commission over her decision to dismiss the charges against a man accused of assaulting a paramedic, Ms O'Shane, 70, was yesterday lambasted by a Supreme Court judge who found her conduct in the traffic case ''fell short of the required standard of a trial judge''.

Justice Peter Garling overturned the magistrate's decision last August to dismiss the police case against Ali Elskaf, who was fined for turning left against a red arrow. The NSW Director of Public Prosecutions had appealed against the decision.

Justice Garling ordered the matter be returned to the local court to be ''dealt with by a magistrate other than O'Shane''.

''In light of … the failures identified in this case I can have no confidence that Magistrate O'Shane would, if this matter was returned to her to complete, undertake the further hearing of it in accordance with the law,'' he said.

Justice Garling found Ms O'Shane threw the matter out of court before the police prosecutor had a chance to make his case, refusing to allow him to present two of his four police witnesses and accusing the two who did give evidence of delivering ''claptrap'' and a ''bag of lies''.

Ms O'Shane told the prosecutor that he could call only two police to give evidence because it was only they who allegedly saw Mr Elskaf run the red light while driving his black Ferrari in Macleay Street, Kings Cross. ''I can indicate to you immediately, sergeant, that it won't assist you in the least,'' Ms O'Shane told the prosecutor when he tried to call the other two police.

Ms O'Shane then told the prosecutor she did not believe the evidence of the first two police and, on

this basis, he did not have a case. ''The court doesn't just accept a bag of lies and say that's enough to establish a prima facie case. In this case that's exactly what I've received,'' she said.

When the prosecutor objected to the officers being described as liars, Ms O'Shane responded: ''Sergeant, I don't want to have to really dot every 'i' and cross every 't' for your benefit.''

Justice Garling found that, in forming her opinion of the witnesses, Ms O'Shane had ignored the fact that much of their evidence had gone unchallenged during cross-examination.

To accuse the officers of lying in these circumstances was ''a clear error of law and a denial of procedural fairness''.

The magistrate had been ''biased'' and had already made her mind up about the case.

She had treated the prosecutor like ''an errant school student'', taking over the conduct of his case, and had been unwilling to listen to his submissions about the strength of the evidence.

''In that respect, her honour's conduct of this matter fell short of the required standard of a trial judge acting properly,'' Justice Garling said.

The judgment is a further blow to Ms O'Shane, whose career is already in doubt after the Premier, Barry O'Farrell, ordered that her behaviour be examined by the Judicial Commission following her decision in a case where she had suggested that a paramedic, Christopher Martin, didn't like ''blacks''.

Justice Garling said it was difficult to understand how she had made such errors, given it was not the first time the ''proper procedure has been … pointed out''.

Last night, the Attorney-General, Greg Smith, said he would be asking the Judicial Commission to consider this latest case in its inquiry into the conduct of Ms O'Shane. She could not be contacted by the Herald for comment.