Opposition agriculture spokesman Nathan Guy said Moving Day had already begun.
"Farmers are moving stock as we speak. What they need is certainty on the decision I believe is going to occur on Monday next week so that they can get some comfort as to what the Government is recommending they do."
Cabinet will decide on Monday whether attempts to eradicate M. Bovis should continue or whether it should move to containment instead.
There are 39 confirmed infected properties at present, with around 12,000 of 23,000 animals culled so far.
O'Connor conceded that "quite a percentage" of the culled cattle were healthy.
"There have been a lot of cows culled. They've been healthy cows but they have been part of a herd that has been identified as infected. That's the horrible reality."
MPI confirmed that police accompanied ministry officials when they executed two search warrants on farms earlier this year.
Police said the Biosecurity Act required that MPI staff were accompanied by a police officer when search warrants are executed. "The police officer takes no part in the search itself."
Police also confirmed they were not involved in the active investigation, which was being run by MPI.