The Ministry for Primary Industries and its dairy industry partners will extend the mycoplasma bovis milk testing under way in Canterbury, Otago and Southland into a national programme from next month.
Mycoplasma bovis is commonly found in cattle globally, including Australia.
It does not infect humans and presents no food safety risk, but can have serious effects on cattle, including mastitis, pneumonia, arthritis and late-term abortions.
In July, MPI said the disease had been detected in a dairy herd in South Canterbury, the first known outbreak in New Zealand, on two of 16 farms belonging to Van Leeuwen Dairy Group.
About 4000 cows have been culled and thousands of tests completed.
Earlier this week, it was also found on a farm in Ashburton, bringing the total number of infected properties to 14.
In a statement, MPI said "while there is no indication that the disease is present beyond the areas currently identified, checking for other possible regional clusters is essential to building a complete picture of the disease in New Zealand".
Every dairy farm will provide three milk samples, with one to be taken from bulk milk and two samples from discard milk, which is milk unsuitable for collection, for example, from cows with mastitis.
MPI said the disease was more easily identified in milk taken from otherwise sick animals.
The programme will begin next month and will be rolled out region by region, with more information set to be provided as details are finalised.