Federated Farmers says Immigration New Zealand's probe into illegal Filipino workers is having devastating effects.
It's believed up to a third of Filipino workers obtained false work experience documents submitted with visa applications.
Federated Farmers Waikato President Chris Lewis says the investigation's slowing down work on the farm.
"I just wish there was some consistency with immigration and [that] they do the proper checks on employees," he says.
"We paid the immigration department a lot of money to do this, so has the applicants, and I wish they followed their own rules, their own guidelines and did a job properly."
Mr Lewis says it's causing slow-downs across the country.