The jury has been discharged in the murder trial of property tycoon Ron Medich because of what a NSW Supreme Court judge has claimed are “completely unacceptable circumstances”.

Justice Geoff Bellew indicated that there was an “incident” in 2013 that caused NSW Police to establish a taskforce but the details of that investigation were not disclosed to Mr Medich until five minutes before his trial was due to start on July 11.

The judge said that the material obtained from the taskforce could have an impact on a principal issue of the trial.

Justice Bellew did not reveal details of what the police investigation concerned but he was scathing about the failure of NSW Police to disclose details of the matter.

“It was not until the morning of the very first day of the accused’s trial, and indeed only minutes before the proceedings commenced on that day, that the material was disclosed to the accused,” the judge said.

Describing the late disclosure as unfair, Justice Bellew said Mr Medich “cannot be forced to go to trial in these circumstances”.

The judge said that, although the detectives involved in Mr Medich’s case were not involved in the taskforce looking at the 2013 incident, it was nevertheless “inconceivable” that those detectives “would not have had some knowledge” of the material relating to the 2013 incident.

Justice Bellew expressed frustration that Michael McGurk was shot dead almost seven years ago but his family would be denied closure “for a further period of time”.

The 45-year-old wheeler-dealer was gunned down outside his Cremorne home in September 2009.

Mr Medich has pleaded not guilty to murder and an additional charge of threatening Mr McGurk’s widow, Kimberley.

Police allege Mr Medich wanted Mr McGurk, his former business associate, dead because the two were embroiled in a series of lawsuits over a soured business venture.

When Mrs McGurk did not drop the lawsuits after her husband’s death, Mr Medich is alleged to have paid thousands of dollars to have her threatened.

At Mr Medich’s 2013 committal hearing, the court heard that the Crown’s star witness, former boxer Fortunato “Lucky” Gattellari, had received $500,000 in cash from Mr Medich to organise the murder and the later intimidation of Mrs McGurk.

Gattellari is serving a non-parole period of 7½ years over his role in Mr McGurk’s death.

No fresh trial date has been set and Justice Bellew has indicated that it is unlikely to start until next year.