High on drugs and short on sleep, Singh believed he had been visited by a witch and was having visions due to her curse.

He told his trucking supervisor, Simiona Tuteru, because he was a church pastor.

"I hadn't had any sleep, I was seeing things, I thought I was cursed by a witch and I was traumatised from it," Singh told the Supreme Court in Melbourne on Tuesday.

The pair searched Singh's truck for items a witch may have left, including voodoo dolls and pieces of hair.

Tuteru then placed his hand on his worker's head and told him: "In Jesus' name I cast a spell out of you."

The Connect Logistics supervisor then allowed Singh to drive the semi-trailer, telling him "you're right to go now" after the prayer and asked him to drive one truckload, Singh told the court.

Singh drove the truck down Melbourne's Eastern Freeway, veered into an emergency lane and struck four Victoria Police officers.

Leading Senior Constable Lynette Taylor, Senior Constable Kevin King and constables Josh Prestney and Glen Humphris, all died at the scene, on the afternoon of April 22, 2020.

Tuteru texted another pastor after the prayer: "Just prayed salvation and deliverance with a driver this arvo, broke curses and witchcraft."

The details were aired in court during Tuteru's pre-sentence hearing after he pleaded guilty to a heavy vehicle offence.

Singh is serving an 18-and-a-half-year prison term for the crash, which was reduced from 22 years on appeal after he agreed to give evidence against his former boss.

He was brought from prison to give evidence to the court on Tuesday, where he took to the witness stand wearing a grey prison tracksuit.

"I was deeply troubled by fatigue," Singh said, about the day of the crash.

However, Tuteru denies Singh told him he was tired before he drove the truck.

Defence barrister David Hallowes SC accused Singh of fabricating his evidence to get a more lenient sentence in his appeal.

"You knew by making a statement against Mr Tuteru that that might help in your appeal," Mr Hallowes asked.

Singh said he was telling the truth about his conversation with Tuteru, but accepted his undertaking to give evidence had helped him reduce his sentence.

Prosecutor Matthew Fisher asked Justice James Elliott to accept Singh's version of events, and said the lack of sleep was "part and parcel" of the conversation about the witch's curse.

He called for Tuteru to be handed a "substantial fine" for allowing Singh to drive before the crash, or a "lengthy" community corrections order.

"This case comes down to one decision by one man," Mr Fisher said.

"Allowing him to get behind the wheel is a sliding doors moment - it should never have happened."

Families of the four victims attended the court, and Const Prestney's brother, father and mother gave statements.

"The night we lost him, I felt like I wasn't there for him and I couldn't protect him," Alex Prestney said.

"It's February 2024 and we are still debating responsibility of how my brother and his colleagues were hit by a 20-tonne truck on the Eastern Freeway."

Justice Elliott will sentence Tuteru, who remains on bail, at a later date.

He was initially charged with manslaughter, but those charges were dropped about six days before he was due to face trial.

Australian Associated Press