An investigation is underway after three puppies were found drowned near Waiuku, south of Auckland

The SPCA was called yesterday afternoon, when a person found the four-month-old puppies while out for a walk.

It appears the puppies were tied up and placed in a bag with a weight.

Northern Region General Manager Jen Radich says resorting to this kind of cruel act is absolutely unnecessary.

She says as the puppies weren't new born someone must know something.

Anyone who has information on who might be responsible is urged to call the SPCA.