"It's hideous, they had gotten cold, which wouldn't have taken long because they were so small, but they were on their last legs when we found them."
While too cold and weak to survive, the puppies otherwise appeared to be in good condition.
SPCA staff were unable to determine how long they had been left there to fend for themselves.
The heartbreaking incident was a reminder people should always contact the SPCA as a first point of call, the spokeswoman said.
"Absolutely and totally people should come to us.
"The emergency phone goes 24 hours a day or they can come to the shelter on the corner of Maraekakaho and Heathcote Roads."
Sergeant Bob Gordon said police liaise with the SPCA to catch offenders who harm or dump defenceless animals.
"Obviously we don't look at it very favourably," he said.