Mr Espinosa, who works for Van Marrewijk Farms in Te Aroha, said many of his colleagues from farms in the area did not get their visas renewed by Immigration and were being forced to leave the country.
"There seems to be a generalisation that all Philippine experience is fraudulent and many genuine farmers are being caught in the net," said Mr Espinosa, who is also the dairy farm workers' spokesman for migrant workers' union Migrante.
He believes because of the difficulties of proving his farming experience and his lack of documentation, he too would struggle to get a new visa when the current one expires.
Immigration New Zealand said it was investigating multiple work visa applications involving Filipino dairy workers, but would not say how widespread the problems were.
Some immigration advisers estimate more than a third who arrived since 2011 could be affected.
Former Philippines consul-general Emilie Shi said "desperate" Filipino farm workers were coming to her for help after failing to renew their visas.
"They've borrowed thousands of dollars to pay for the documents, and they are worried about what will happen to them when they go back."
Many in the Philippines saw overseas work as the only way to support their families because of a lack of opportunities back home, she said.
"They will look for education and qualifications that will help them get these overseas jobs, and dairy farming and healthcare are popular industries for Filipinos coming to New Zealand. Most are poor and simple folks who may not know that the documents they paid for are fake or that what they are doing is wrong."
One dairy worker in Matamata said he paid about $10,000 to a dairy farm in Manila for papers to show he had been working there for the past 10 years although he was there for only three months.
"I have been a farmer my whole life, more than the 10 years the documents showed, so I don't feel like I am lying or that it is a fraud," he said. "It is just something I had to get in order to meet New Zealand immigration requirements."
Philippine minister and consul-general Arlene Gonzales-Macaisa said the embassy in Wellington was working closely with Immigration and the Ministry of Social Development.
Despite Immigration's assurance that it is still processing visas from Filipino dairy workers and continuing to approve individual applications, many are facing problems in getting their visas.
Farm worker Florante Bajo, 40, has decided to withdraw his application after a four-month wait to renew his work visa.
"They want my social services and remittance proof from the Philippines, which I do not have," he said. "I feel I am an innocent victim to this whole investigation. I decided to withdraw and go home rather than risk being blacklisted and banned from New Zealand."
Albert Villaneuva, 35, has work waiting for him in Ashburton but has been without a visa for about two months. He had been working on a dairy farm for a year but applied for a change in visa to work in pig farming.
"Every day that I cannot work means another day without money, and I am worried about running out of money," he said.
Farm owner and employer Michael van Marrewijk said his experience with the two Filipinos he had employed had been "excellent".
"The work ethics of Filipino workers is a lot better without a doubt and that's why I don't mind taking them on at all."
Mr van Marrewijk was worried about how the immigration investigation and delays might cripple farm operations.
"I agree there's fraudulent activities going on and I don't agree with that, but I also know that many farms are dependent on these migrant workers to keep going."
He wants Immigration to give employers the choice on whether to retain workers already here.
"Go directly to employers ... even if a worker has come over and is fraudulent, but is able to ... handle the responsibilities, he should be treated accordingly."
An Immigration spokesman refused further comment as the investigation was ongoing.
