By Peter Wilson
A "small number of cowboys" in the livestock industry are responsible for animal cruelty, Parliament has been told.
Primary Industries Minister Nathan Guy gave MPs an assurance the inquiry into bobby calves being kicked, beaten and killed is a top priority.
Shocking footage of the cruelty, screened at the weekend, prompted widespread condemnation.
"The ministry will be very thorough ... this is very similar to a police investigation," Mr Guy said.
"In my view it is the action of a minority - a small number of cowboys - in the industry."
Mr Guy earlier told reporters he hoped those responsible would be prosecuted.
He says the farms where the cruelty was filmed have been visited and his department's inquiry is continuing.
The animal welfare organisation SAFE released the footage after handing it over to the ministry.
"MPI stepped up the investigation on September 14, as soon as they got the footage, and visited the farms in October," Mr Guy said.
He doesn't think it will have a big impact on New Zealand's exports.
"We are considered to have the strongest animal welfare standards in the world," he said.
"We strengthened our laws earlier this year."