All seven people arrested following the discovery of a cannabis farm at Gibbett Site Pig Farm on Hale Road in Bradenham on Sunday have now been bailed.
All have been bailed until the end of January 2014.
The two men aged 20 and 31 and one woman aged 45, believed to be foreign nationals, remain detained at Wymondham Police Investigation Centre on behalf of immigration authorities.
Seven people remain in custody following the discovery of what Norfolk Police are calling "one of the largest cannabis farms" that the force have dealt with in recent history.
Police were called to a commercial property in Bradenham.
Officers found a "highly organised and sophisticated operation” at Gibbett Site Pig Farm on Hale Road.
During searches that evening, a cannabis production operation was located within a building at the site and a 30-year-old man was arrested at the scene on suspicion of cultivation of cannabis.
During the search, a second building containing approximately 200 large sacks of raw tobacco was discovered.
It's estimated that the combined total of products seized is over £1 million.
– Chief Inspector Ady Porter, Breckland Commander
"Information received by police led to a significant police response in order to maximise the safety of all concerned.
"The farm is in an isolated location and the cannabis factory was discovered in one of many outbuildings on the site with 20 separate rooms given over to cannabis production.
"Every room was set up for production from seedlings to mature plants with extensive hydroponic equipment.
"In our view this is a highly organised and sophisticated operation and one of the most significant in recent times.”
A cannabis factory has been discovered at a commercial property in Norfolk. Police were called to Hale Road in Bradenham just after 8.40pm Sunday.
Five people have been arrested in connection with drugs offences and enquiries continue.