Port Stephens-Hunter detectives dismantled hydroponic set-ups at Aberglassyn, Chisholm, Raworth, Heddon Greta and two at Tenambit on Wednesday morning.

Police have linked the “grow houses” to an Asian crime syndicate. Three men and a woman, all Vietnamese nationals, were arrested during the operation and taken to Maitland Police Station.

Port Stephens-Hunter crime manager Detective Inspector George Radmore said the houses were exclusively used for cultivation, with “crop sitters” used to keep a close eye on the set-ups.

Investigators said the hydroponic set-ups in each house were extremely sophisticated, featuring scores of fake walls, watering systems, growing lights and transformers.

Police spent several hours at the homes seizing various items including lighting and sophisticated power boards. Power company technicians were also called in to disconnect illegal electricity supplies at each of the homes.

Port Stephens-Hunter Commander, Detective Superintendent Craig Jackson, said police were investigating suspected links between the properties as the investigation showed “all the hallmarks of organises crime activity”.

Superintendent Jackson urged the public to continue to inform police about suspected drug operations in the Hunter.

“One of the houses today featured a baby walker in the garage and Christmas lights rigged up outside in a bid to blend into the neighbourhood,” Supt Jackson said.

“But there are tell-tale signs to look out for.

“So-called hydro houses can give off a pungent odour, activity at the properties tend to be very low key, and windows are often always shut or boarded up.”