The suspected Class B drugs were found in two vehicles during a stop and search at Dargan Road, north Belfast, on Tuesday evening.
Two men, aged 36 and 24, were arrested on suspicion of possessing a Class B controlled drug with intent to supply.
The pair are currently assisting police with their enquiries.
The vehicles have been seized for further examination.
Appealing for anyone with information about the seizure to contact the PSNI, Det Insp Keith Gawley said: "This was a proactive policing operation which has stopped a huge amount of drugs from entering Northern Ireland."
Police in Belfast have seized herbal cannabis with an estimated street value of about £1m.