Nationwide milk testing for mycoplasma bovis will begin next month in a bid to control the devastating cattle disease.
Mycoplasma bovis, which causes lameness, mastitis and abortions in cows, has now infected 14 farms, from Hawke's Bay to Southland.
The latest case was confirmed on an Ashburton farm this week.
The Ministry for Primary Industries said the disease was "not a food safety risk", but extending the milk testing programme that was currently underway in Canterbury, Otago and Southland would identify any other regional clusters and build a complete picture of the outbreak.
The programme involves testing three milk samples from every dairy farm. One sample would be taken from bulk milk as part of the regular sampling process at milk collection.
Farmers would also be required to provide two samples from "discard milk" - milk unsuitable for collection, for example, from cows with mastitis.
That was in addition to the existing nationwide mycoplasma bovis surveillance activity, which includes tracing animals from infected and suspect farms, vets looking for signs of the disease, testing animals with symptoms, and testing all mastitis milk sent to laboratories.
The programme was expected to begin in February and would be introduced region by region, the ministry said.