Mohammed Nchouki, 40, took the witness stand in the ACT Magistrates Court on Wednesday as part of a bid for bail.

The one-time Nomads chapter president has pleaded not guilty to four charges, including threatening or intimidating a witness in judicial proceedings, over a tapped phone call recorded on May 23.

Mr Nchouki was captured speaking to brother Jomal about how he was going to find and "f---" the wife of a police officer and how he would "cave in" the head of someone, alleged to be the same officer.

The prosecution alleges Mr Nchouki knew police were monitoring his calls, citing times he made references like "that f---en dog who is listening to us right now".

But Mr Nchouki insisted he was only "trash-talking" with his brother, unaware anyone else would hear what he said.

"It was just stupid," the builder told the court on Wednesday.

"It was just trash talk. [I was] just trying to make him laugh, just trying to reassure him."

Mr Nchouki said he could tell his younger brother, who has been charged with drug trafficking, was upset after an interaction with the police officer discussed in the call earlier on the day in question.

He said it was not his intention to put fear into anyone's mind, saying he was "just joking" in an effort to "make [Jomal] giggle".

"You ever trash talk at all?" Mr Nchouki asked prosecutor Patrick Dixon.

Quizzed on whether he knew police were tapping his phone at the relevant time, he replied: "Absolutely not."

Jomal Nchouki also gave evidence on Wednesday, telling the court he had been concerned police were spreading rumours about him being "a dog".

He said officers including the one mentioned in the phone call had visited him and encouraged him to "snitch" on people.

Jomal told the court he thought Mohammed was "just trying to cheer me up", and that he did not think the 40-year-old was making genuine threats against anyone.

"That's how he always talks to me," Jomal said.

The court heard on Wednesday it was crucial to the prosecution case to prove Mr Nchouki knew his calls were being listened to or recorded.

Defence barrister Steven Whybrow said there was no evidence of this and the charges were "doomed to fail".

"The charges are ... of a bizarre and confected nature," he said.

Mr Whybrow said police appeared to have "aided and abetted" the alleged offences because the officer in question would never have known about the contents of the call unless a colleague, who listened to a recording the next day, made him aware of it.

But Mr Dixon, opposing bail, argued the officer named in the call was always going to find out what had been said because "the police weren't just going to sit on it" after hearing the recording.

He also disputed the characterisation of the conversation as merely "trash talk" or "banter".

"[Mr Nchouki] moves in and out of speaking to his brother and then he's back on to [the officer] again," he said, noting that Mr Nchouki was not laughing.

Magistrate Louise Taylor remarked that Mr Nchouki seemed to be doing "a fairly bad impression of a B-grade gangster film" in the recording.

Mr Nchouki made a noise at this point as if he was about to burst out laughing, prompting his wife to make a shushing gesture from the public gallery.

Ms Taylor continued: "This is not a cold, clinical assertion [of threats] because of the ranting style of it. I mean, every second word is f--- or c---."

Mr Dixon replied: "Whilst they mightn't have been sophisticated or detailed threats, they were threats nonetheless."

Ms Taylor indicated she would make a decision on the bail application this coming Wednesday.

Our journalists work hard to provide local, up-to-date news to the community. This is how you can continue to access our trusted content: