Macdonald, 70, Obeid, 76, and the latter's son, Moses Obeid, 50, have pleaded not guilty to conspiring together for Macdonald to wilfully engage in misconduct as a minister between 2007 and 2009.

The plot allegedly involved the rigging of a tender process for a coal mining exploration licence on Obeid land at Mount Penny, in the Bylong Valley near Mudgee, for the family's financial benefit.

The NSW Supreme Court judge-alone trial began in February before Justice Elizabeth Fullerton, who adjourned it for a fortnight on March 15 amid public concerns over the spread of the COVID-19 virus.

"Until then the accused can stay in glorious isolation," she noted.

But technical issues arose when the parties returned on March 27, conferring virtually to examine the feasibility of running much of the trial online.

Chief Justice Tom Bathurst has banned all physical appearances in the state's highest courts except in "exceptional circumstances" due to the pandemic.

At the time, the trial was only five weeks into its scheduled 26 weeks.

Justice Fullerton said she had explored every means for which leave might be granted for a physical trial.

Asking the parties to give the online trial "a red-hot go" and see if some headway can be made with at least a few witnesses, she promised to not allow the process to undermine the interests of the accused and the prosecution in having a fair trial.

But the online idea was abandoned on Monday, when the trial was adjourned until August 31, with the case to be mentioned on August 3.

Australian Associated Press