The Ministry of Agriculture & Forestry is de-stocking a West Coast farm after having to put down more than 30 starving cattle that were too sick to be moved.
MAF says a member of the public alerted it to the plight of livestock on Lake Brunner Station, inland from Greymouth.
Compliance and enforcement director Geoff Allen says there were about 1000 dairy and beef cattle there.
MAF has been working with Federated Farmers and the farm manager to move the surviving animals to other farms.
Mr Allen says it is a case of insufficient feed and too many animals, with inadequate supervision to ensure they were looked after.
He says the priority for MAF at the moment is dealing with the animals, but once that has been done, MAF will be looking to see if a prosecution needs to be laid.