Millionaire property developer Ron Medich has been found guilty of ordering the execution-style murder of a former business associate after their relationship turned sour.

Key points: Medich shook his head as the verdict was handed down

Medich shook his head as the verdict was handed down This was the 70-year-old's second trial. The jury at his first one failed to reach a verdict

This was the 70-year-old's second trial. The jury at his first one failed to reach a verdict The court was told Medich and Michael McGurk had done multi-million-dollar deals, but that their relationship soured

Michael McGurk, 45, was shot in the head at close range after pulling up outside his Cremorne home on Sydney's lower north shore in September 2009.

The married father-of-four had just picked up a takeaway meal for dinner, and one of his sons was in the car at the time.

Medich, 70, pleaded not guilty to murdering Mr McGurk and later intimidating his wife Kimberly McGurk, but after more than five days of deliberations a jury found him guilty of both crimes.

Medich leaves the Supreme Court a guilty man. ( AAP: Brendan Esposito )

He turned bright red in the face, and shook his head as the verdict was handed down.

He passed his wallet, phone and keys to his lawyer before being led away by corrective services officers.

Medich went on trial in the New South Wales Supreme Court in late January, in what was his second trial for these offences after a jury failed to reach a verdict last year.

Outside court, Mr McGurk's wife Kimberley said the past eight-and-a-half years had taken a toll.

Kimberley McGurk described it as a "great day" for the justice system. ( ABC News: Mazoe Ford )

"The damage to my family will never be repaired but the result will allow my family to move forward," she said.

She thanked the NSW Police, and the prosecutors.

"[It's] a great day for justice and the jury system of NSW," she said.

"My children and I would like to thank everyone involved in the process from the bottom of our hearts."

'Embarrassment, anger and frustration'

During the trial, Crown prosecutor Sharon Harris told the jury Mr McGurk and Medich had once been involved in multi-million-dollar business partnerships, including property developments and financing.

However, Ms Harris said that by March 2009 their relationship had become "extremely hostile" and they were locked in expensive legal battles in the Supreme and Federal Courts.

She said Medich was feeling "embarrassment, anger and frustration" and had developed a hatred for Mr McGurk.

"These disputes were a significant motive for the accused to direct the murder of the deceased in 2009 and then the intimidation of his wife in 2010," Ms Harris said.

Fortunato Gattellari (R) pleaded guilty to his role in the murder of Michael McGurk (L). ( AAP: Mick Tsikas / ABC News )

The court was told Medich turned to his close friend and former boxer Fortunato 'Lucky' Gattellari to "permanently resolve" the disputes by arranging the fatal shooting.

Gattellari pleaded guilty to his role in the murder and received a discount of 60 per cent on his sentence after agreeing to help prosecutors and give evidence against his co-accused.

During the trial, defence barrister Winston Terracini SC was scathing of Mr Gattellari's credibility, telling the jury the Crown's star witness was a "spiv" and a "crook" who told "a multitude of lies" while he was in the witness box.

Mr Terracini said the Crown's case was based on Gattellari's evidence and if the jury did not believe his version of events they could not convict his client.

Three of Gattellari's associates have also been sentenced for their roles in the murder.