Federated Farmers says the organisation bringing in a new national livestock identification scheme still has a lot of work ahead of it to get farmers on board.
The NAIT company has confirmed the scheme will take effect for dairy and beef cattle from July next year, when it it will be compulsory for farmers to put radio frequency ear tags on their cattle and register them.
The programme will be extended to deer the following year but there are no plans to include sheep at this stage.
NAIT says it will be writing to farmers next month to provide more detail, including plans for tag and slaughter levies to help pay for the programme.
It says many farmers are already preparing and have bought more than four million electronic ear tags so far.
However Federated Farmers president Bruce Wills says there's still a lot of confusion and anxiety among farmers about the details of how it will work and the NAIT company has a task ahead clear information to the programme users.
He says Federated Farmers accepts the NAIT scheme is inevitable because it has enough support in Parliament to become law next year.
But the ACT Party says it will oppose passing the National Animal Identification and Tracing Bill because it says the scheme is costly and unnecessary.
Former Federated Farmers president Don Nicolson, who's now an ACT candidate, is also calling for a farmers-only referendum to be attached to the legislation, and says the scheme should be delayed until 2017, when there will be improved broadband services in rural areas.
