Bovine tuberculosis has been detected in cattle in Northland, a region that's supposed to be free of the disease, for the second time in four months.
Up until this year, bovine TB hadn't been found there in eight years, but despite the latest infections the area has kept its disease-free status.
The detection was made at a farm in the same area, Awanui, where the earlier outbreak was found, although the agency responsible for TB herd testing, the Animal Health Board, doesn't believe the two cases are linked.
Its Northland regional manager, Frank Pavitt, says it seems the infection in both cases was caused by diseased cattle being introduced to the herds from another area.
All the stock movement rules appear to have been followed, Mr Pavitt says, but the infected animals were still able to get through undetected.
He says the board is looking at tightening up movement controls in particular areas and around infected properties.