Mr Mullen, 32, who is serving a four-year ban from rugby league after he tested positive to an anabolic steroid in 2017, is alleged to have supplied cocaine on four occasions at Cameron Park during November last year.

The former Knights' star and one-time NSW Origin representative was allegedly caught in the net of a large-scale drug syndicate operating between Newcastle, Lake Macquarie and Sydney last year.

Mr Mullen, now living in Tarrawanna, a suburb of Wollongong, appeared in Newcastle Local Court on Thursday charged with three counts of supplying an indictable quantity of a prohibited drug and one count of supplying a traffickable quantity of a prohibited drug.

His lawyer Paul McGirr told the court Mr Mullen would be pleading not guilty to the charges.

"At this stage I can say that, I just want to see the brief (of evidence)," Mr McGirr said.

Deputy registrar Jason Mortimer ordered the police brief of evidence be provided to Mr Mullen's legal team by July 18. Mr Mortimer adjourned the case to August 8 and continued Mr Mullen's conditional bail. Court documents were silent on the quantities that Mr Mullen is alleged to have supplied on four occasions between November 23 and 30, 2018.

But the threshold for an indictable quantity of cocaine is more than five grams of the drug, while the threshold for a traffickable quantity is between three and five grams, according to the Drug and Misuse Trafficking Act.

The more serious charge carries a maximum of 15 years in jail if prosecuted in the district court or a maximum of two years in jail in the local court.

It was unclear in Mr Mullen's matter whether the Office of the Director of Public Prosecutions (DPP) was going to elect to prosecute the matter in the district court.

Strike Force Castlestead detectives arrested Mr Mullen at his home in north Wollongong on May 29.

He was the eighth person charged by the strike force after detectives raided a number of homes in December last year and arrested alleged syndicate head Matthew Shane Pearce, 35, of Cameron Park, his brother, Brett Robert Pearce, 33, of Wangi Wangi, Leslie Charles Mason, 40, of Mayfield, engineer Jay Edward Ramsden, 28, of Kingsford, and Aaron Macey, 28, of Rose Bay.

All but Mr Ramsden remain behind bars, having been refused bail and awaiting trial for their charges.

Detectives arrested and charged Ty Andrew Hopley in February as well as four other men who remain before the courts.