The drugs, found in Co Down, have been valued at €1.47m
A sixth person has been arrested following a major herbal cannabis seizure in a cross-border operation.
Officers have seized what they believe could be one of Northern Ireland's largest ever hauls of herbal cannabis.
PSNI Detective Superintendent Bobby Singleton said: "This seizure of herbal cannabis yesterday is estimated to be worth in the region of stg£1.3m (€1.47m).
"It is the largest seizure for some time, and we are delighted to have been able to take these drugs out of circulation, in collaboration with our partner agencies."
It was intercepted and five people were arrested by PSNI officers during a search of a property in Dromore, Co Down on Friday.
Three men - aged 32,37 and 72 - and two women - both aged 68 - were arrested by PSNI officers following an operation involving An Garda Síochána and Revenue Customs Service.
The operation was conducted under the banner of the Cross Border Joint Agency Task Force.
The drugs were found concealed inside an industrial-sized fuel tank on a shipping pallet at a property in Dromore.
A number of follow up searches and enquiries were subsequently carried out at other locations.
Detective Superintendent Bobby Singleton added: "We are continuing to investigate but at the moment, we believe these drugs are linked to the activities of an organised crime group, operating in Northern Ireland."
A sixth person, a 42-year-old woman, has also been arrested on suspicion of a number of drugs charges.
The two 68-year-old women and the 72-year-old man have been released on bail pending further police enquiries.
The 32 and 37-year-old men remain in custody, along with the 42-year-old woman.
Speaking earlier, An Garda Síochána Assistant Commissioner Barry O’Brien said: "I wish to commend all agencies involved in both jurisdictions which resulted in the seizure of a substantial quantity of controlled drugs.
"This demonstrates the practical application of the Cross Border Joint Agency Task Force."
PSNI Assistant Chief Constable Stephen Martin added: "This seizure and the associated searches and arrests demonstrate the effectiveness of the real time intelligence sharing and cross-border collaboration that takes place daily to tackle serious and organised criminality in both jurisdictions.
"With the assistance of our colleagues in An Garda Síochána and Revenue Commissioners we have undoubtedly prevented the significant harm that would have resulted from this huge consignment of drugs reaching the streets of both Northern Ireland and the Republic of Ireland today."