The trial had been scheduled to last six weeks, with the Crown calling evidence from 150 witnesses.
McGrath disappeared in May 2017 and his body has never been found. He was last seen at his Halswell home on May 21 that year.
The 49-year-old carpenter's failure to show up for a weekly Tuesday dinner at his mother's home sparked a missing person's inquiry followed by a homicide investigation, dubbed Operation Renovation.
Benbow was held in custody from the time of his arrest in September 2019, until he succeeded with a bail application and was released on strict conditions in November 2021.
Justice Rachel Dunningham made the order delaying the trial at a hearing on June 9, but suppressed the reporting of the delay until today - at the request of Crown prosecutor Barnaby Hawes - so that the families and witnesses could be advised.
It is the third adjournment for the trial. Defence trial preparations were affected by the death of lead defence counsel Margaret Sewell in November 2021, and now Covid-related issues have caused the further delay.
Open Justice multimedia journalist
