Dairy farmers fear a mass expulsion of Filipino workers who lied on their CVs would cripple their industry.
Immigration New Zealand said a visa document scam had exposed a widespread problem of workers exaggerating their experience and qualifications to get jobs on dairy farms.
It has been investigating false visa applications, and on Tuesday arrested a recruiter for fraud.
"It is claimed that the woman used New Zealand employers' details without their knowledge in order to secure work visas for Filipino nationals offshore to work in the New Zealand dairy industry," it said.
Visas of Filipinos in the dairy industry are now being scrutinised, and some are at risk of being sent home.
One Filipino worker, who did not want to be named, said people lie about their experience and qualifications because they're seeking a better life.
"Why do the workers come here? They come here for their family so they can give them money," he said.
"If some people use fake documents, they're thinking about a good future in their life - that's why so many Filipinos leave."
Mely Feria is an immigration coordinator in the South Island and said the blame should fall on recruiters who encouraged deception.
"These are the people who benefit - they charge people large sums of money, and these people aren't even rich," she said.
"Lives are being jeopardised, it's not just the worker, it's the whole family who depend on their income."
Immigration New Zealand's assistant general manager, Peter Elms, said the department would be lenient to some workers, but hard on others.
"The prospect of sending large numbers of people back could be quite devastating for some farms," he said.
"In many cases, the extent of the fabrication is on the minor side of things - it's an exaggeration of work experience - but where we do find that people have lied consistently to us, they're less likely to get our discretion."
Ms Feria said she hoped for an amnesty.
"That's our prayers - that Immigration will focus on recruiters, because they're the ones who entice people and give the wrong information."
Immigration New Zealand said there were about 1700 Filipinos in the dairy industry on work visas.
Federated Farmers' Otago dairy chair, Stephen Crawford, said a mass exodus would be devastating.
"In the south, we rely pretty heavily on migrant workers and it's quite difficult to get skilled workers on our farms and these guys are very good," he said.
"Someone putting a little white lie on a CV, I don't think that would just be Filipino workers, but something that's common in a lot of places."
An immigration consultant, Ben De'Ath, guessed up to 600 Filipino dairy workers had fudged their CVs, and half of them had lied in such a way they were risking their visas being cancelled.
"It would cripple farms. You've got a lot of health and safety legislation and animal welfare rules that you've got to abide by, and to be able to comply with that, you've got to have staff on farms," he said.
"Even now you've got worker shortage on a lot of farms."
Immigration New Zealand said it would work closely with the dairy industry to make sure there would be workers left on the farms.