The Government's Labour Inspectorate is taking enforcement action against 19 dairy farm owners for employment law breaches.
Inspectors who visited 29 dairy farms around the country in their latest round of checks found two thirds of them were not complying with employment rules.
Most of the breaches related to poor record keeping, but in several cases farmers had underpaid their workers, with estimated arrears of more than $120,000.
Labour Inspectorate's Central Regional Manager Natalie Gardiner said the high level of non-compliance was concerning.
"We did actually target a number of those farms due to information about non-compliance in the employment area, so we were expecting there to be high non-compliance. We also have a number of farms who were fully compliant during the audit so that was good to see, but on the whole there was widespread non-compliance with just about every aspect of employment legislation.
Ms Gardiner said the labour inspectorate was looking to file nine of the more serious cases with the Employment Relations Authority.
"Fifteen improvement notices have been served, so they will identify what the breaches were that the employer has made in those cases and how they can remedy those, and that may include paying arrears to their employees, if they're owed.
"In several cases the labour inspector is preparing documents for the Employment Relations Authority which outline arrears owed to employees and some of them are quite significant."
Ms Gardiner said dairy farmers could expect ongoing visits from labour inspectors, as they followed up the large number complaints they get about employment practices on farms.
Federated Farmers said it was also disappointed with the poor results from the latest round of dairy farm labour inspections.
National dairy chair Andrew Hoggard said despite all the effort that it and other organisations had been putting into improving farmer employment practices, the message still was not getting through with some farmers.
"Some of the farms they visited were targeted based on previously coming to their notice, and some were random, so that will skew the results slightly higher, but that's still far too high a number for the industry and we'll definitely need to do more to sort this issue out.
"You know we've had a long standing tradition of operating in a certain manner, probably based on historically being sole charge farms, with just the owner or maybe working with family members or one other employee, working side by side and that's how our attitudes have formed around work.
"Then, as the farms have grown bigger, more and more staff have been involved and we do need to change some of those attitudes and how we look at work."
Mr Hoggard said lifting employment standards would remain a high priority for Federated Farmers.
It had developed industry standard employment contracts for farmers, holding Employment Compliance Workshops that had been well attended and was also developing a new Workplace Accord with DairyNZ and other industry stakeholders to be launched next month.