The puppies, seizes from the boot of a car were all too young to travel, had no passports and although microchipped, were not registered on any approved database.
The puppies were seized by the Scottish SPCA as part of Operation Delphin which is targeting the illegal trade in puppies from Ireland to the UK and were returned to Ireland where they originated from.
It is believed these puppies were sourced in the County Louth area and investigations are continuing.
ISPCA CEO Dr Andrew Kelly said: “I would like to thank Police Scotland, Stenaline and Customs officials in Cairnryan and Belfast for their swift action in this case.
“This was a horrific way to transport these vulnerable puppies and the person they were seized from had no regard for their welfare.
“We do not know exactly where these puppies originated from in Ireland but our investigations are continuing. The ISPCA believes it is time for a crackdown on illegal behaviour by dog breeders in Ireland and is calling on all local authorities to enforce the DBE legislation robustly and to take action where breeders fail to comply.
“Unfortunately we have seen a lack of consistency in the enforcement of the regulations. In one county a registered breeder licensed for 100 breeding females had over 500 dogs on site when inspected and in another county the ISPCA discovered an unregistered breeder and reported it to the council who simply invited them to register.”