The three - a 44-year-old woman and two men aged 30 and 40 - are due to appear in court this afternoon.
A 42-year-old man also arrested over the find has been released pending a report to the PPS.
Five other men arrested in Belfast, Newtownards and Manchester as part of the investigation remain in custody.
Police said 10 searches had been carried out at locations including Manchester, Derry, Belfast, Newry and Newtownards.
Documents, cash, phones, jewellery and small quantities of suspected drugs have been seized.
Detectives from the Organised Crime Branch worked with police from Greater Manchester, the National Crime Agency, the North West Regional Organised Crime Unit and Police Scotland on the investigation.