The farmer asked the council who the stock belonged to, but he said they could not tell him and they could not they access the NAIT records.
Blackwell said the farmer tracked down the rogue heifers' owner himself.
Federated Farmers believed councils needed to do more work to get on top of continued ignorance around Mycoplasma bovis risk and how to use the country's animal tracking system, NAIT, Blackwell said.
"Gone are the days where you can just stick cattle anywhere and walk away pretending it's not your problem.
"What would have happened if those wandering stock were sick and had contaminated the healthy animals or vice versa? Would that council pay out compensation to the injured parties? It's not pleasant watching your stock get sick."
Blackwell did not identify the local council involved.
Biosecurity was the responsibility of all New Zealanders - Federated Farmers strongly encouraged local councils to play their part, he said.
"Federated Farmers has gone to great lengths to promote the message to councils and are frustrated that it hasn't got through."