Cattle in a dairy herd in the Awanui area north of Kaitaia have been found to be infected with bovine tuberculosis.
The infection - a major blip in the region's long TB-free status - has brought a quick response from the Animal Health Board (AHB), which has clamped movement controls on animals in the herd and is testing neighbouring herds.
Cows identified with TB in the infected herd have been withdrawn from milking. While drinking raw milk from the rest of the herd could contain an element of risk for humans, the pasteurisation milk goes through in commercial processing eliminates danger of infection.
The AHB has also started annual TB testing for cattle and deer herds within 10km of the infected property. They were formerly tested every three years.
Two dairy herds in the same area were diagnosed with TB in 2009, but AHB Northern North Island co-ordinator Frank Pavitt said yesterday diseased animals had been slaughtered and those herds had since tested clear of infection.