Owners of three Christchurch properties where sheep were killed and maimed by dogs want the dogs' owners to front up.
Joshua Olykan said he came home to his parents' Hei Hei property on Saturday morning to discover 14 animals dead or badly injured.
"I discovered one sheep behind the factory, then I saw some limping around with their ears ripped off there was blood everywhere."
Mr Olykan had the hard task of putting down sheep that were still alive after the brutal attack.
He said 21 sheep, the majority of which were in-lamb ewes, were killed or had to be put down across three properties.
"Hind legs were torn to shreds, wool was torn off their bodies and most of them had their jaws crushed so it was pretty horrific."
Mr Olykan said this was the third time sheep at his parents property had been killed by dogs in the past 20 years.
He wants the owners of the dogs to come forward.
"If someone in this area has noticed their dog covered in blood, they should come forward so the right thing can be done."
Phil Stewart, who has 25 sheep on the neighbouring property, found some of his sheep with bad injuries.
He said he was lucky that none had to be put down, and he was taking precautions in case the dogs return.
"I will move most of these sheep away, I am going to pen them up at night, but I have set a trap and so has dog control."
Laurie Williams who runs a chicken farm next door said the seven dead sheep on his property all had wounds to their heads.
"My employees thought it was done by smaller dogs because they have gone for the face where as bigger dogs usually go for the throat."
Mr Williams said he had never noticed dogs around the area before.
Animal behaviour expert Elsa Flint said dogs were predators so owners had to be responsible.
"The majority of dogs will be stimulated by a flock of moving sheep ... in most of these cases you see it start as a play activity, chasing and barking, but then it switches and they take it too far."
Christchurch City Council animal control is investigating, and police have been advised of the attack.