Five dogs were seized at Dublin Port on Friday in two seizures by Revenue officials.
The dogs, four 12 week old Spaniel cross pups and one adult Terrier were lacking paperwork for transport to the UK and had not completed vaccinations.
Two men who were travelling to the UK separately were stopped and questioned in relation to the dogs.
The men did not have pet passports for the dogs as required under the Animal Health and Welfare Act 2013.
All the dogs were transferred into the care of the DSPCA who are
conducting a follow-up investigation.
Revenue works closely with the DSPCA and other bodies to combat illegal puppy trading.
This is the third seizure of dogs in the port this week alone.
On Tuesday night, two Chihuahuas hidden in the boot of a car leaving for the UK were uncovered.
Only one of the dogs was microchipped, there were no pet passports or rabies vaccines and the dogs vaccination certs were actually for eight week old puppies.
