John McLeod regularly conducted business for the decorated soldier after meeting in Brisbane in 2011, and considered him a "friend" when he was handed a blue folder with envelopes and names in 2018, he said in evidence on Wednesday.

That evening Mr Roberts-Smith telephoned him saying "got (those) addresses for you buddy," advised not to post two of four enclosed letters, and how to identify a remaining recipient being Person 18, he said.

The following morning en route to pick up a family heirloom from his aunt's house and while searching for a fish and chip shop fronting the Tweed River, he posted the letters.

About a week later after the ex-police officer was "summoned" by Mr Roberts-Smith to a meeting in Milton when he yelled from a footpath "no phones no phones".

Mr McLeod said he turned his phone off and the pair walked to the side of the building where Mr Roberts-Smith asked if he had

"seen the media".

"They're saying the letters were threats ... they're not f***ing threats. It's just a touch-up," Mr Roberts-Smith allegedly said.

"I didn't understand what he was saying and then the penny dropped," Mr McLeod said.

He told Mr Roberts-Smith that if compromised him by his actions he'd "better get me a good lawyer".

"I said 'if you've done something stupid put your hand up ... the cover-up is 10 times worse than the offence'."

He said Mr Roberts-Smith told him to "just say you were a supporter of mine," and sent the letters because he was "sick of the way I was being treated".

"I just looked at him and said 'f*** that you weak dog'."

Mr McLeod "ceased" contact from that point, he said.

The Victoria Cross recipient is suing The Age, The Sydney Morning Herald and The Canberra Times for defamation and denies their reports that he committed war crimes and murders in Afghanistan between 2006 and 2012.

The 43-year-old has strenuously denied all wrongdoing including allegations of facilitating the threatening letters.

The newspapers' barrister Nicholas Owens SC asked Mr McLeod whether he had ever spoken to journalists about his dealings with Mr Roberts-Smith.

"No, I despise the media," he said.

Mr McLeod said he agreed to post the letters after Mr Roberts-Smith said he "was under the pump" and too busy himself.

It followed another surveillance mission he was tasked to perform at a Brisbane termination centre in 2018.

After parking outside the Greenslopes abortion clinic for several hours, he figured the woman codenamed Person 17 "had gone to the wrong hospital," a short distance away, he said.

After relocating he saw his target leaving Greenslopes Hospital, a centre he had confirmed did not perform such procedures, and sent a recorded video to Mr Roberts-Smith.

Mr Roberts-Smith testified that he asked Mr McLeod to follow the woman because he suspected she was lying about being pregnant.

Mr McLeod said odd jobs he performed for Mr Roberts-Smith included pretending to be a bartender at a home function he was hosting for Channel Seven employees.

It was soon after Mr Roberts-Smith had taken a top job at the media company and was interested to know what the staff "thought of him," he said.

Barrister Bruce McClintock SC, on behalf of Mr Roberts-Smith, said Mr McLeod was big-noting himself and had been hired as a doorman to check on guests.

"Not true," he said.

He agreed he later referred to Mr Roberts-Smith as a "prick" and "psycho".

Australian Associated Press