Growing concern Mycoplasma bovis could be here to stay.

Fourteen properties have tested positive for the cattle disease, all but one are in the South Island.

New Zealand Farmers Livestock, general manager Bill Sweeney said many farmers in the North Island are avoiding buying cattle from the South, due to uncertainly over where the disease may have spread.

"I think most farmers in all honesty believe that the horse has probably bolted and that it has been out there a lot longer than it actually has been."

Livestock Exchange, general manager Scott Perkins said there's a growing frustration at MPI, with farmers facing long waits to get animal blood test results back from the Ministry.

"We blood tested our heifers, it took two months for the results to come back, they told me it was going to take a week and they couldn't find the results."

None of Perkins' stock tested positive for the disease.