A 31-year-old man from Greenleigh, NSW, has been arrested and charged with drug offences as part of Operation Athos, a joint investigation by police in the ACT and Victoria.

Police say that in August the joint investigation set out to identify and disrupt a criminal group allegedly distributing significant quantities of controlled and prescription drugs including Xanax, Valium, anabolic steroids, human growth hormone, clenbuterol, THC gummies and psilocybin chocolates.

Three men were arrested in the ACT as part of this investigation in December when police seized millions of dollars worth of unprecedented quantities of controlled drugs as well as about $200,000 in cash, a house, five vehicles, three motorcycles and designer goods in simultaneous drug raids across the ACT and interstate.

At the time it was described as the largest illegal controlled and prescription drug distribution network ever identified in the ACT and Victoria.

Further investigations have identified the alleged involvement of another man, the 31-year-old from Greenleigh.

On Thursday police from the ACT and NSW searched the Greenleigh residence, where the man was arrested, while ACT police also searched a residence in Conder.

As a result of the Greenleigh search warrant, police seized:

•    About 450 grams of cocaine
•    About 160 grams methamphetamine
•    About 145 grams MDMA

Biggest drug bust ever for ACT police