The Ministry for Primary Industries "strongly suspects" a cattle disease has spread to Otago.
MPI said in a statement this morning that blood results from a third South Island farm, in the Oamaru area, showed some animals had been infected with the bacterial cattle disease Mycoplasma bovis.
The farm had a direct connection with one of the infected Van Leeuwen Dairy Group's South Canterbury farms and had received some animals from the farm before the disease was first found in New Zealand.
MPI response director Geoff Gwyn said as a result, the property was now under a "restricted place notice", controlling the movement of animals and other risk materials off the farm.
“There is no need to name the farm concerned.
"The farmer has been in regular contact with us and has voluntarily kept stock and risk goods on the farm for more than three weeks while our testing has taken place," Mr Gwyn said.
"No animals have left the property since 20 July. However it is understood that before this, some animals were moved to a number of other farms.
"MPI is contacting those properties and is testing animals with urgency."
Mr Gwyn said at this time, there was no clear evidence the disease was on those other properties.
MPI was considering whether the farms would need to have specific controls placed on the movement of risk goods.
“In the meantime, we’re asking the farmers concerned to follow good on-farm hygiene measures and to ensure their NAIT records are kept up to date in case there is a need to trace animals in future.”
Mr Gwyn said the new development was not a sign the disease was running rampant in New Zealand, but was evidence the extensive surveillance and testing programme was working.
“Part of our response has been identifying and investigating animals that have moved from affected properties earlier this year."
"Buying, selling and moving stock is a common practice in farming and it was always possible further infected properties would be found.
The positive tests were not a "game changer", he said.
"Along with the animal industry bodies, we remain committed to continuing the biosecurity response, finding any infected properties, controlling the disease and, if possible, eradicating it from the country.
“The disease is being well contained on the known properties and we are confident our control measures are sufficient to contain it there.
"Our surveillance programme continues to investigate whether the disease had been spreading around the country before it was discovered in South Canterbury.”
MPI had a range of checks and testing underway to get a picture of what was out there.
As well as the checks on the Van Leeuwen farms, neighbours and trace properties, it was testing samples supplied through regional veterinary laboratories and through a survey run by Massey University, and working with dairy companies to look at the milk from animals in the Waitaki and Waimate districts.
MPI encouraged all farmers and rural contractors to help protect their farms and businesses by following standard on-farm hygiene best practice.