A long-time friend of AFL star Ben Cousins conspired with another man to traffic 45kg of MDMA or ecstasy, a Perth court has heard.

Fabian Quaid, 33, a one-time aspiring Olympic athlete and mate of Cousins, is on trial in the West Australian Supreme Court, charged with conspiring with others to take possession of MDMA powder after it arrived in WA on a cargo ship last year.

Dimitrios Papadimitriou, 39, of Queensland, is also on trial for the conspiracy.

Both men have pleaded not guilty to the charge.

In her opening address to the jury, prosecutor Gillian Braddock showed the court videos and photographs taken during a covert police investigation last year.

Ms Braddock said security footage, filmed at Fremantle port on the night of April 16 last year, showed a small boat, with no lights on, moving away from a commercial ship.

She alleged those on the boat removed two bags of MDMA powder weighing 45kg from the cargo ship that were later uncovered by police during a secret search of a granny flat in Lockridge, in Perth's northeastern suburbs, on May 8.

Investigators replaced the drugs with a fake substance so they could continue to monitor the house, she said.

Recorded phone conversations, photographs and video evidence would form the basis of the prosecution's case against Quaid and Papadimitriou, Ms Braddock told the jury.

Police have alleged both men are members of an international drug syndicate that was the focus of the police operation that led to the bust.

Defence lawyers Con Heliotis QC and Michael Tudori said about 500 taped telephone calls to be used as evidence in the case could be misinterpreted.

Mr Heliotis said "most of the prosecutor's facts are not in dispute ... but don't confuse fact with theory."

He said while prosecutors had presented examples of phone recordings, and their possible meanings, they were not correct.

Ms Braddock said that in the phone calls the accused would speak in code, calling Sydney "Sarajevo" and Perth "Christina".

Mr Heliotis said despite the police surveillance Quaid was never seen at the Lockridge flat and never found to be in possession of drugs.

"The interpretation the prosecution has put on this case to make (the phone calls) fit the theory is in dispute," Mr Heliotis said.

He said Quaid did speak and meet with other people involved in the case but it had nothing to do with conspiring to traffic drugs.

Claims Quaid was talking in code to the other accused about drugs, when referring to menus and restaurants was disputed by Mr Heliotis.

He said at the time of the phone tapping, Quaid, who was living in Manly, was looking to buy a cafe in Sydney.

Quaid had tried to gain selection for the Sydney 2000 Olympic Games in the martial arts event of taekwondo.

Mr Heliotis also argued his client's involvement in the recorded phone conversations and the prosecutor's claims he was given code names, like "the young one" and "F", could be misinterpreted.

Acting for Papadimitriou, Mr Tudori reminded jurors there were two separate people on trial.

He mirrored Mr Heliotis's defence for his client, that the phone recordings could be misinterpreted and the recordings were "not as clear as (prosecutors) would like".

The trial is set down for six weeks, before Justice Lindy Jenkins.