The Commerce Commission has confirmed that it is investigating livestock companies and the fees they charged when the national animal identification and tagging scheme (NAIT) was introduced three years ago.
The NAIT scheme required cattle and deer to have electronic ear tags linked to a national database, so individual stock could be traced.
It was designed to improve New Zealand's ability to respond quickly to a food safety scare or a biosecurity threat.
The commission said it had been investigating alleged price fixing by three New Zealand livestock companies and five individuals for more than a year.
The companies are PGG Wrightson, Elders New Zealand and Rural Livestock Limited.
A commission spokesperson said it was reviewing the prices that were charged when the scheme was introduced and it hopes to file proceedings against the companies and individuals by the end of this month (July).
Elders New Zealand chose not to comment and PGG Wrightson and Rural Livestock did not return calls from Radio New Zealand.