Herbal cannabis and amphetamines were among the drugs discovered.
Drugs worth over €370,000 have been seized in the midlands and Dublin.
Revenue officers discovered 17.6 kgs of herbal cannabis and 1 kg of amphetamines, worth around €368,000, during an examination of parcels over the past week.
€5,000 worth of other illegal drugs were also seized.
They were in parcels which originated in the USA, the UK, the Netherlands, Spain, Canada, Thailand and India, and were intended for addresses nationwide.
Revenue officers also seized a quantity of retail goods, with an estimated value of over €28,000, due to infringements of Intellectual Property Rights.