The incident occurred near Clara in Offaly and the puppies were found dumped in the river Brosna.
There were 7 puppies in total, but one escaped the bag in which they were trapped and survived.
The collie pups were put into an old fertiliser bag, which was then weighed down with stones, tied and tossed into the river.
The Local Offaly county council Litter warden was the man who made the discovery yesterday after he heard squealing coming from the river bank whilst walking by.
He then jumped down and recovered the one surviving puppy.
Anyone with any information on the incident is asked to contact the Offaly County council office