The Otago SPCA is investigating the death of four puppies found in Lake Dunstan this week.
Cromwell mum Fiona Stewart told Stuff she was walking with her three primary-school-aged children near the town's historic precinct on Tuesday when she found four large black-and-white puppies.
She said her children were "horrified" at the discovery.
"[It was] very confronting and upsetting for the kids.
"Ironically we were doing a treasure hunt and were searching in the driftwood [when we found them]."
The children were "heartbroken" to think someone could do something like that, Ms Stewart said to Stuff.
"They just don't understand it."
Ms Stewart said the puppies were not newborns and had been dead for a while.
"Those responsible need to be held accountable. There is no need for this. It's disgusting really.
"There are so many wonderful agencies out there to help you if you have unwanted pets," Ms Stewart said to the news organisation.
SPCA Otago director of animal welfare Helen Beattie said it was investigating the incident, but did not want to comment until it had a "more accurate picture".
