Ho Ledinh, 65, was shot dead in broad daylight at the Happy Cup Cafe at Bankstown City Plaza on January 23, 2018.

Abraham Sinai, 36, has pleaded not guilty in the NSW Supreme Court to murdering the solicitor.

In the crown opening address on Tuesday, prosecutor Sean Hughes said a man called Arthur Keleklio used a .45 calibre handgun to shoot Mr Ledinh three times.

While Sinai did not pull the trigger, the Crown contends he is guilty of murder because he was part of an arrangement or agreement for the solicitor to be killed in that way.

Mr Hughes said the jurors could infer that Sinai knew what was to happen as Keleklio walked armed towards Mr Ledinh, particularly due to his movements in the hour leading up to the shooting.

CCTV and other evidence relating to the shooter and Sinai would lead to "a very strong conclusion that they were acting together and that their going to Bankstown that day was together far from innocent".

In the weeks before the murder, there was phone contact between the two men and other evidence may provide a possible motivation for Sinai to become involved, Mr Hughes said.

"I expect you will hear evidence that Mr Sinai, in his own words, was an enforcer for a man named Khai," he said.

"I expect you will hear evidence that he collected debts on this man Khai"s behalf; that he used an encrypted phone service, namely a BlackBerry mobile device to communicate with Khai."

The prosecutor expected the jury would also hear evidence that sometime before August 3, 2017, Mr Ledinh claimed Khai owed money to a client of his, Tri Nguyen.

"I expect you will hear that he was upset Khai owed, this man Khai owed him money and that he was keen to find out where Khai lived," Mr Hughes said.

"So there's an association between on the one hand Mr Sinai and Khai, and Khai and the deceased."

Speaking through an interpreter, Thang Duc Nguyen testified that he had overheard Mr Ledinh having a "loud" phone conversation one morning at the cafe, during which he swore and spoke about a man named Khai.

"He said something about money being owed and not paid."

He said he told the solicitor he knew a man called Khai and he asked if he knew where he lived.

Fetuiai Siloi testified that his cousin Sinai's nickname since he was a young teenager was Sniper, his Call of Duty gametag.

He also was called Mahki, Samoan for Mark.

On three occasions he had gone with his cousin when he collected debts from "family", although not blood relatives, who had borrowed money.

Giving evidence via AVL from California, Dang Chau Nguyen said he used to supply encrypted phones and towards the end of 2017 met a man called Khai, who requested a BlackBerry.

Khai offered him the drug ice when they met, which he accepted, and "he got me hooked onto it".

In November 2017, he was introduced to a friend of Khai, known as Sniper, whom he was told was an "enforcer" who took care of Khai's debt collecting.

"Someone who uses strength to intimidate someone," he said.

The trail continues before Justice Robert Allan Hulme

Australian Associated Press