A judge has issued an arrest warrant for Sydney construction boss George Alex, who failed to show up to court as directed after being found guilty of conspiracy to defraud the tax office of more than $10 million.

Alex was one of four people who faced a marathon six-month trial in the NSW Supreme Court, who were found guilty of conspiracy to cause loss and conspiring to deal in the proceeds of crime.

The jurors delivered their final verdicts against 53-year-old Alex on Tuesday this week and he was granted bail to appear before Justice Desmond Fagan today for a detention application.

But Alex didn't show up.

Instead, he dialled into the hearing on a video link from Northern Beaches Hospital, where he's receiving treatment for an addiction to opioids.

'No alternative' to issuing arrest warrant

Justice Fagan asked for an explanation from Alex's barrister, John Agius SC.

"I don't have one, Your Honour," Mr Agius replied.

Mr Agius then told the court his client was due to be assessed by a consultant psychiatrist some time on Friday to ascertain whether he had the ability to attend court.

Mr Agius argued for the warrant to be issued but not be acted upon pending Alex's attendance at court.

But the judge said he would not tolerate the situation and Alex had been extended "considerable latitude" during the long trial.

His co-accused were remanded in custody when jurors reached verdicts regarding their offences in late August.

Alex appears on screen from rehab

Justice Fagan said when one verdict was returned against Alex in late August, he accepted that Alex was suffering "significant withdrawal symptoms" and his treating doctor wanted to get him in a better state given his very high intake of non-prescription opioids.

Mr Agius said Alex had commenced a program of buprenorphine and had been accepted into a rehabilitation program, hoping to stay in that program for three weeks.

During the hearing, Alex remained on the screen, with a shaky camera and frequently closing his eyes.

Justice Fagan said realistically, it was "inevitable" that a significant period of incarceration would follow.

Mr Agius argued there were exceptional circumstances because if Alex was taken into custody his access to intensive physiotherapy for an emaciated leg would be impacted.

But Justice Fagan said Alex had been able to attend the court daily during the trial until the 99th day, when jurors retired to consider their verdicts.

"Mr Alex was able to come in here, sit in the back of the court, move around … I didn't require him to sit in the dock," the judge said.

"He was able to come and go. He was able to do all of that."

Justice Fagan said "suddenly" when the verdict was returned against him, a picture was presented of Alex having issues with a large intake of opioid intake, amounting to him "effectively going on a bender" at the end of the evidence.

Court told Alex could lose his leg

Mr Agius told the court that the potential price Alex would pay for a delay in physiotherapy and other treatment was "the loss of his leg".

He said his client was not "just an addict off the street" but someone who became addicted to relieve pain.

Mr Agius said his client was at risk of having to spend the weekend at a police station.

"There's an alternative," Justice Fagan replied.

"That your solicitor could ring him at the Northern Beaches Hospital and discharge himself, and get a taxi.

"It's just moved out of your hands, and out of the hands of the legal team."

Justice Fagan issued the arrest warrant and is now expecting Alex to be brought before him in person.