Reports that some dairy farmers aren't allowing some trucks onto their farms because of Mycoplasma bovis have come as no surprise to biosecurity officials.
The Ministry for Primary Industries (MPI) says 37 farms have confirmed M bovis infections.
RadioLIVE Rural Exchange co-host Richard Loe has heard from fertiliser truck drivers that some dairy farmers aren't allowing them on-farm because they don't know where the trucks have been.
Geoff Gwynn, MPI's director of response for M bovis, told Rural Exchange he agreed with this level of scrutiny.
"I think you should know everyone who comes on to your property," he said. "You should also have areas [on your farm] that are no-go zones for contractors."
Almost all regions in New Zealand now have at least one infected property.
Despite the spread, Mr Gwynn said every property is connected to MPI's network with a trail of infected properties that shows the links between each one and where they trace back to.
"The fact they're still part of the same network and we can connect them to that network is critical to understanding whether we can eradicate or not," he said.
MPI has now performed at least one round of testing across 10,500 out of 12,000 dairy properties in New Zealand.
"To date, we've only had three positive finds," said Mr Gwynn. "Those three are properties we were already aware of. So it's very encouraging, but a little too early to pop the champagne corks."
Listen to the full interview with Geoff Gwynn above.