Labour inspectors are checking out working conditions on North Island dairy farms to make sure they are complying with the employment laws.
They began visiting dairy farms in Southland in August and have extended that to include Waikato, Manawatu, Taranaki and Bay of Plenty
The visits are part of a long-term operation to identify breaches of employment law.
Labour inspectorate central region manager Kris Metcalf said they found some of the Southland farms visited were not complying with employment rules.
"We visited 10 farms in the Southland area. We found about 30% of them didn't have accurate wage and time records," Mr Metcalf said.
"What it boiled down to is they didn't have enough records for us to establish the hours worked and, when we reverted back to their employment agreement to establish the hours, many were working excessive hours requiring a top-up of wages or limiting their hours worked for the future."
Three farms were served with an enforceable undertaking for non-compliance in those areas, he said.
North Island farms on the inspection list would include farms the inspectorate had previous dealt with, as the result of complaints about workers not receiving the correct pay or being exploited in some way.
Inspectors would visit farms in Northland and other parts of the South Island next year and would also check on migrant labour conditions on dairy farms, Mr Metcalf said.
The checks coincide with the release by Federated Farmers of a new practical guide for farmers hiring overseas people because they can not get staff here.