Royal Mail staff identified 28 suspicious parcels which were later found to contain drugs.
A large amount of illegal drugs were found in parcels destined for Cambridge addresses. Royal Mail staff contacted police after identifying 28 suspicious packages over the weekend.
The parcels were intercepted and found to contain 500g bags of cannabis, which is a Class B drug.
A Cambridgeshire Police spokesperson said: "Their vigilance has prevented a significant quantity of illegal drugs from reaching our streets. An investigation is now underway into the importation of controlled substances.
"A huge thank you to the Royal Mail team for their swift action."