Police have arrested four allegedly low-level Vietnamese operatives and will investigate whether they are linked to a criminal syndicate after the discovery of up to 1400 cannabis plants which police estimated had an estimated potential street value of $2.8 million.

But the huge haul came as no surprise to senior police, who have over the past two years dismantled nearly a dozen grow houses across the Hunter and put several other Vietnamese nationals behind bars.

Strike Force Devom detectives conducted the coordinated raids on six homes in Raworth, Tenambit, Heddon Greta, Aberglasslyn and Chisholm about 8am.

It is alleged the homes were fronts for an extremely sophisticated cannabis growing operation.

More than 400 mature plants were unearthed from one home alone.

The homes allegedly contained dozens of grow lights, hundreds of meters worth of wiring, fake walls and watering and ventilation systems.

It is alleged all the homes were bypassing the electricity supply to feed power into the homes.

Police spent hours transferring the cannabis plants into rental trucks and were still counting the haul by the afternoon. Police confirmed up to 1400 plants were found – a significant haul even in comparison to other major cannabis busts in recent years.

It is alleged the electricity supply had been bypassed to feed more power into the homes.

Police spent hours transferring the cannabis plants into rental trucks and were still counting the haul by the afternoon. Police confirmed the haul topped 1405 plants – a significant haul even in comparison to other major cannabis busts in recent years.

Four men and a woman – all Vietnamese nationals – were arrested at the scene and were charged with cultivating a large commercial quantity of a prohibited plant.

Two men, 37 and 26, were also identified as being illegal immigrants, police said. 

Police will allege the four were “crop-sitting” at the properties.

Port Stephens/Hunter Detective Superintendent Craig Jackson said those alleged to be behind the grow houses had made attempts to blend in – including positioning the baby walker and installing Christmas lights out the front – but there were still obvious signs.

Detective Superintendent Jackson warned there could be other houses across the Hunter that carry sinister secrets. He said the pungent smell of cannabis, boarded-up windows and low-key activity at the homes were all “tell-tale” signs. “They will do everything they can to fly under the radar … [but] they do not present as your typical neighbour,” he said.

The raids are the first major cannabis bust since detectives raided an alleged grow house in Newcastle’s Steel Street in October.

More than 300 plants were unearthed during that raid and a 44-year-old nail salon owner, Newcastle’s Nga White, charged with knowingly directing the activities of criminal group. Several of her alleged associates were also arrested.