"She's harder than him," Mr Medich allegedly told associates, referring to her late husband, before paying for her to be intimidated.

A wealthy property developer, Mr Medich, 68, has pleaded not guilty to ordering the 2009 murder of his former business partner and the subsequent intimidation of Mrs McGurk.

But in the NSW Supreme Court on Thursday, a Crown witness said Mr Medich was "under pressure, angry" when discussing Mrs McGurk.

At the time of the murder, Senad Kaminic was a driver and debt collector for Medich associate Lucky Gattellari.

Gattellari pleaded guilty to arranging the shooting, while Kaminic pleaded guilty to acting as an accessory after the fact.

In return for his testimony against Mr Medich and others, he received a shorter sentence and indemnity against other charges, including those regarding the widow's intimidation.

Kaminic, a former Bosnian soldier, has told the jury Mr Medich had wanted a hit man to "go all the way" and kill Mr McGurk.

The pair had been battling over millions of dollars in court after several business deals fell through.

"If I had a gun, I would have killed him," Kaminic recalled Mr Medich saying in 2009.

Conspirators originally discussed a plot in which a woman would become "friendly" with Mr McGurk and inject him with a lethal overdose of drugs. Shooting became the preferred option.

Gattellari said Mr Medich handed him Cryovac bags of cash for the murder in two lots of $250,000 on separate occasions at the Medich home, in the presence of Kaminic.

However, Kaminic said one payment of $250,000 was made via a cheque which he picked up from Mr Medich's office. Another time, he received $150,000 in a bag when he went to pick up Mr Medich and drop him to the airport, he said.

He delivered different sums of money to one of the men who eventually carried out the hit. Then, on September 3, he received a phone call to say "the tyres are done", code for the execution of Mr McGurk.

Mrs McGurk rushed out of her Cremorne home that night to find her husband slumped in his car in the driveway, a hole in the back of his head.

She has told the court that one August night, 11 months later, a shadowy figure appeared outside her window to tell her "I should do the right thing and not be a thief like my husband and pay my debts."

Mrs McGurk felt "sick, shaky" and "very frightened".

Kaminic told the jury on Thursday that Mr Medich would refer to Mrs McGurk as a "bitch" who was "harder than him", meaning her husband.

He said one of the men who murdered her husband, Haissam Safetli, offered to intimidate her for $100,000.

According to Kaminic's evidence, Gattellari checked with Mr Medich to see if that would be too expensive. Then the word came back that he should engage Safetli to scare off Mrs McGurk, he said.

Kaminic's evidence continues.