The new national livestock identification scheme, NAIT, becomes compulsory for cattle on Sunday.
That means people in charge of cattle need to register with the scheme, tag and register their stock, and record when animals move off-farm. Deer come under the scheme in March next year.
The scheme is designed to improve New Zealand's ability to respond quickly to a food safety scare or a biosecurity threat.
It requires the use of electronic ear tags linked to a national data-base to provide traceability of individual cattle and deer.
NAIT has had a bumpy road, with Federated Farmers among others questioning the necessity and the cost to farmers.
But NAIT chief executive Russell Burnard says more than 30,000 cattle and deer farmers have registered for the scheme so far, nearing half the estimated 68,000 cattle and deer herds.
Mr Burnard says newborn animals need to be tagged and registered from 1 July but there is a three-year transition period for other stock.
He says cattle being moved also need to be tagged and recorded straight away, unless they're going to the works.