Fifty puppies have been seized by gardai at Dublin Port en route to England.
The pups are said to be in a good condition and are now up for adoption.
The so-called 'designer' dogs were discovered in a van by gardai, port staff and an animal welfare group yesterday.
The animals are now in the care of the Dublin Society for the Protection of Cruelty to Animals (DSPCA) and are receiving veterinary attention.
Gillian Bird of the DSPCA said the discovery was the latest in a string of attempted smugglings in 2016.
"This is the seventh seizure in the last two months," she told the Herald. "That brings the total number of puppies found in that time to 150.
"On the market here, they would probably be around €200 or €250, but if you sell them in the UK, you could get €800 for them."
At present, it is still unclear where the puppies came from, but Ms Bird said an ongoing undercover investigation could reveal more answers.
None of the puppies discovered had the required pet passports when found. All were also under the legal age for export.
"We're looking at everything - reputable breeders, backyard breeders and puppy farms," she said - adding the puppies are not thoroughbreds, but many are mixed breeds such as Cockapoos and Pugaliers, and could be worth €34,000.
Other popular breeds discovered in the van included Beagles, Bichon Frise and Cocker Spaniels.
It comes weeks after Store Street gardai seized 22 puppies and a pregnant dog from Dublin Port.
Earlier in August, a further 14 dogs were found in the boot of a car at the port.
Ms Bird also said the pups, which were probably in transit for about four or five hours, were healthy and doing well.
"These animals were actually ok, but some of them were very wary," she said. "Two of them were quite dehydrated and we have them on a drip now."
The pups are now up for adoption, but the DSPCA stressed that they will be highly selective when picking new owners. Those interested should meet with a DSPCA adoption consultant in Rathfarnham to see if they are suitable.