A CLOSE business associate of a property tycoon accused of the murder of a Scottish businessman in Australia was intimidating and volatile when alone, a court has heard.

Millionaire Ron Medich is on trial over the murder of his former business partner Michael McGurk, 45, who was originally from Govan and was gunned down outside his home in Sydney on September 3, 2009.

His working partner Fortunato "Lucky" Gattellari has already been convicted for his part in organising the killing, but agreed to testify against Mr Medich.

The 68-year-old's defence team say that Mr Gattellari, 66, devised the murder on his own to cloak thefts he had made from Mr Medich,

Kim Shipley, an accountant who worked for both men, said that Gattellari could be frightening when hounding people for money, and reserved his "most poisonous" language Mr McGurk.

Mr Shipley, who began work in 2008, told the NSW Supreme Court on Tuesday the three would discuss business over lunches costing AUS$500 or AUS$600.

But when he tried to resign, he realised Mr Gattellari "wasn't someone to say no to". "We know where your daughter lives in London," he recalled the former boxer telling him.

Several days after Mr Gattellari's arrest in 2010, Mr Shipley attended a meeting at a Martin Place office with Mr Medich and his lawyer.

Mr Shipley asked on his boss's behalf for Mr Medich to transfer AUS$1 million into a lawyer's trust account for legal fees.

"Don't be bloody silly," Mr Medich allegedly responded, before saying "He's on his own." Mr Shipley recalled Mr Medich had an "air of concern" and his hands shook.

"Watch what you say, the walls have ears," Mr Medich allegedly told him.

Mr Gattellari, who received a shorter prison sentence for testifying against Mr Medich, said in his own evidence "I have never threatened anyone".

The Trial, before Justice Geoffrey Bellew at the Supreme Court in New South Wales, continues.