An underground cannabis factory in the Ballyward area was under surveillance for six months, the High Court has heard.
Officers swooped on the purpose-built subterranean complex containing £350,000 worth of drugs after covertly recording suspects, prosecutors said.
Five men were arrested in the operation at a shed on the Derryneill Road May 21.
One man, Mark Cavanagh, faces charges of cultivating and possessing cannabis with intent to supply.
The 39-year-old, of Killutagh Rise, Glenavy, County Antrim, was refused bail by the judge who said planning chiefs would have been impressed by the sophisticated extent of the factory’s construction.
Searches of the premises uncovered three separate rooms containing drugs at different stages of growth.
A total of 600 plants were seized, along with lamps, hose piping and other equipment.
Walls were professionally fitted, wired and connected to an electricity source 262 ft (80m) away.
“It’s described by police as unique in Northern Ireland - a purpose-built underground factory,” a prosecution lawyer said.
“The police have been carrying out an operation and recorded evidence within the last six months over a series of dates.”
She claimed surveillance footage shows Mr Cavanagh at the scene, and audio recordings place him “in the bowels” of the shed.
The accused denies any involvement in the cannabis-growing operation or witnessing any illegal activity.
A lawyer for the defence said his client had a viable case, pointing out that he was not near the pit when police arrived.
But after studying photographs from the scene the judge refused bail.
“The evidence against him is that he was present at what can only be described as a very impressively constructed and designed cannabis factory,” he said.
“Indeed, I’m quite sure that had it been subject to a planning application the degree of care, money and technology that went into it would have impressed the planners had they not known the real purpose of it.
“Now that this factory has been discovered there may well be all sorts of repercussions for those who saw fit to put so much money into its construction.”