Apart from emergencies farmers will be unable to kill calves on farms with ''blunt force'' to the head from June 13.
The ban has been welcomed by farmers themselves, with Federated Farmers among submitters seeking a change to the code of welfare for dairy cattle outlawing it as a routine method.
Primary Industries Minister Nathan Guy confirmed today that killing calves with a hammer or other blunt device would be ruled out, except in unforeseen emergency cases.
He said the decision followed directions by him in February for the National Animal Welfare Advisory Committee (NAWAC) to advise on euthanising calves on farms by manual blunt force.
''NAWAC concluded that on balance manual blunt force trauma as a routine method for killing calves is not acceptable, and should be only reserved for unforeseen emergencies.''
Most of the 357 submissions received by the committee supported the proposed changes to the code of welfare for dairy cattle.
The code will be reissued with amendments covering the humane destruction of calves on farms and come into effect ahead of this year's calving season.
''The code states explicitly that calves must not be killed by the use of blunt force trauma caused by a blow to the head, except in unforeseen emergencies,'' said Guy.
The Ministry for Primary Industries is working with the dairy industry to ensure that training is available for farmers in alternative methods such as the use of a captive bolt.
Guy said New Zealand had a world leading animal welfare reputation to live up to and this mattered to New Zealanders and international consumers of our animal products.
Federated Farmers has welcomed the approaching ban and the provision of its use in emergency situations.
Animal welfare spokesman Willy Leferink said Federated Farmers was one of many submitters supporting the change to the code of welfare for dairy cattle
"Euthanising any animal requires great skill to achieve rapid death.
''This is a skill not everyone is up for due to obvious reasons and we are grateful the code revision agrees. Any of the recommended methods require genuine skill. It is why we look forward to working with the Ministry, DairyNZ and veterinarians to ensure that the right training is available to farmers. No matter what method is used, we believe death must be swift and confirmed before the animal is left.''
He said farmers would appreciate the committee recognising the emergency use of blunt force as the alternative was for farmers to carry a weapon every time they went on-farm, which was neither safe nor sensible.
"Emergencies can happen anywhere on-farm involving sick and injured stock or calves that are born with deformities or injuries. The quickest and most humane act may in fact be blunt force trauma.''