At Auckland District Court Tuesday morning, prosecutor Joshua Shaw Mendoza represented the Crown, which said Russell Mendoza and Tony Campbell went on a "commando exercise'' in January 2010, shooting to death 33 of their neighbour's dogs including puppies.

Shaw told Auckland District Court Mendoza had planned the shooting because he believed his dog had been mauled by another dog which happened to belong to his neighbor, Rowan Hargreaves.

Mendoza and Campbell went to Hargreaves' 5-hectare rural property near Wellsford, north of Auckland, Shaw told the court. He added Mendoza took with him a note which he got Mr Hargreaves to sign. The note said the two men could shoot the dogs and there would be "no comeback.''

First, the men spotted two dogs in a van and shot both of them in the head, making two "reasonably clean kills.''

Then they saw a cage where eight dogs were kept and began shooting from both sides, Shaw told the court.

"It was clear that they were not killed instantly. They suffered considerable stress as well as pain,'' Shaw said.

Then the two men moved to a campervan where more than 20 puppies were kept.

Shaw said there was no indication that the puppies could have been involved in the mauling of Mendoza's dog, but the pair was intent on killing all the puppies, only one of which had escaped.

SPCA (Society for Prevention of Cruelty to Animals) worker Sacha Keltie appeared in the court as a witness, saying she removed the bodies of eight dogs from a cage. She noted the bodies of the young puppies, some only four weeks old, all had bullet wounds.

The trial continues. The case is heard only by a judge; no jury is involved, APNZ reported.