Two properties near Inglewood in Taranaki are being tested for Mycoplasma bovis.
The Ministry for Primary Industries said it was the first time M. bovis testing had been conducted in the region, RNZ reported.
Notices of direction restricting the movement of animals had been issued by the ministry.
The report quoted the MPI as saying most farms under notices of direction do no end up testing positive for M. bovis.
The MPI said last week the number of infected properties stood at 41 - five in the North Island and 36 in the South Island.
A lifestyle block property in Rakaia, Canterbury had been confirmed as positive and tracing work from its 24 animals was underway.