Omarjan Azari, 24, is on trial in the NSW Supreme Court for doing an act in preparation for, or planning, a terrorist act in a telephone conversation with Baryalei at 9.03pm on September 15, 2014.

On Monday, Mr Azari pleaded guilty to a second charge of financing a terrorist group by sending thousands of dollars overseas to foreign fighters.

In his opening address on Monday, Crown prosecutor Peter Neil, SC, said that Mr Azari recruited a "young, impressionable Muslim boy" to do the transactions as Mr Azari felt he was under too much surveillance.

However, the 17-year-old boy blew his cover when his mother picked up a pair of cargo shorts to wash them and found $9200, bound for Islamic State, accidentally left in the pocket.

The boy, a university student, will give evidence against Mr Azari, Mr Neil said.

The jury heard a transcript of the telephone call at the centre of the case between Mr Azari and Baryalei, a former Kings Cross bouncer who fled to Syria in 2013.

In the 20-minute call, Baryalei said: "What you guys need to do is just pick any random unbeliever. Finish him or her. When you finish, put the flag of the state in the background."

Baryalei said he'd give the video to Islamic State's media arm and it would be used to show Australians that by "killing our people" Australians would be killed in return.

He said he wanted the work to be "continuous" and to preferably involve western tourists or backpackers as it would make "worldwide news".

"I want you to do this work but I want this work to be continuous," he said. "Terminate five, six, seven people a month and we will make videos and videos and videos."

He told Mr Azari it was an order from the "commander of the faithful" and that Mr Azari should select two or three boys "with perfect faith" to do it with him.

"They want youse to be, like, the soldiers [in Australia]," he said.

"I have no problem with that," Mr Azari replied.

Mr Azari suggested that he be given two months to get a new phone and to allow time for the "extreme" surveillance on him and his group of 17 young friends, who met at Parramatta Mosque and called themselves The Shura, to subside.

"What, do you think now [the authorities] are hearing our conversation or not?" Baryalei asked.

"Most likely, yeah," he replied.

The defence case is that Mr Azari was trying to make excuses to get out of the proposed plan.

Defence barrister John Stratton, SC, said that Mr Azari was aware Baryalei was a senior member of Islamic State who had indirect control over Mr Azari's two older brothers, who had both travelled to Syria to fight.

In the three days between the phone call and Mr Azari's arrest on September 18, he did "absolutely nothing" to advance the plan, Mr Stratton said.

He said there will be a dispute over the translation of the call, which was in a mix of English, Arabic and Dari, and that Mr Azari said he wanted to "abandon" the plan, not postpone it.

"What the accused is clearly not doing is agreeing to take part in a terrorist act," he said.

In the phone call, Mr Azari and Mr Baryalei allegedly spoke about using a jahil, a religiously ignorant person, to carry out the killings.

Mr Neil said Mr Azari had similarly befriended the 17-year-old boy at Parramatta Mosque in 2014, who later attended money transfer businesses for Mr Azari.

Mr Azari has pleaded guilty to those charges.

On one occasion, the young boy was worried the transfer fees were too high for Azari so he took the cash home, where it was later discovered by his mother.

His parents confiscated it and handed it to police when their home was raided.

The trial continues.