Sydney millionaire Ron Medich has been jailed for at least 30 years for directing the execution-style murder of a business enemy and the intimidation of his widow.

The 70-year-old property developer was found guilty in April of the contract murder of Michael McGurk, who was shot dead outside his Sydney home in September 2009, and the intimidation of Kimberley McGurk almost a year later.

In the NSW Supreme Court on Thursday, Justice Geoffrey Bellew described the murder as an abhorrent and heinous crime before jailing Medich for 39 years with a non-parole period of 30 years.

The jury accepted the evidence of his former confidant, Lucky Gattellari, who said Medich masterminded and financed the shooting of the 45-year-old wheeler and dealer.

He was gunned down after he and Medich had become embroiled in ongoing and protracted legal battles involving millions of dollars.

“I am satisfied that by the early part of 2009, the decline of the relationship between the offender and Mr McGurk … had led the offender to form a deep-seated hatred and provided him with a motive to have him killed,” the judge said.

“I am satisfied the offender paid in the vicinity of $500,000 to have Mr McGurk killed.”

The decline of the relationship … led the offender to form a deep-seated hatred and provided him with a motive to have [Mr McGurk] killed

The “violent, sudden and unexpected” death of Mr McGurk had a catastrophic effect on his family, Justice Bellew said.

Extending his deepest sympathy to them, the judge said they had gone through “the most severe emotional upheavals that could ever possibly be managed”.

Gattellari testified that Medich said he had been made a “laughing stock in the eastern suburbs”, that Mr McGurk was ruining his reputation, and he wanted Mr Gattellari to find someone “to take care of this guy”.

Gattellari said he asked Medich if he was sure about the murder, saying “there’s no going back”, and he replied: “I am sure. I want him done.”

The star crown witness was sentenced in May 2013 to at least seven years and six months in jail after admitting organising the murder. He got a 60 per cent discount for his guilty plea and helping authorities.

Medich is the sixth man to be sentenced over the murder.

-AAP