Nearly 50 Chinese construction workers are asking the government to hold to account a man they believe has conned them of tens of thousands of dollars.
The workers were brought to New Zealand by a man called Peter Li, also known as Wenshan Li, and they said he promised them jobs where they could earn $6400 a month.
One builder, Mao Qun You, said he was told he would earn much more than that.
Mr Mao arrived in the country last November after paying Mr Li nearly $57,000 to arrange a working visa.
When he asked why this visa was so expensive, Mr Li assured him it was worth it.
"He said the visa he would arrange was different; his was the best visa because my whole family could eventually move over as well.
"He said eventually I could make millions of New Zealand dollars."
But he has only made about $25,000 so far, working 50 hours a week.
Mr Mao called Mr Li in March to ask for his money back so he could return to China.
"He told me I was dreaming [and] tried to blackmail me saying he had been in New Zealand for 26 years.
"He told me not to cross him and said I wouldn't be able to do anything against him."
Mr Mao hoped the government could hold Mr Li to account.
Other workers RNZ spoke to said they paid Mr Li about $40,000 to help them apply for working visas.
They were promised about $6400 a month for work, but none of them were earning that.
They all have valid working visas.
Another worker, Fan Guo Hua, arrived almost four months ago.
He said as soon as he got off the plane he was taken to Tauranga by Mr Li.
Mr Li assured him there would be work and everything was legal.
But week after week passed and there was not any work.
"He kept telling us to be patient and three weeks later I started working a couple of days here and there.
"I only worked about 80 hours [in total]."
Mr Fan said he had only been paid $800 for that.
Since August, the workers said Mr Li had brought about 48 workers from China to New Zealand.
But in the last month, none of them had been able to reach Mr Li on his mobile phone.
He did not respond to any of RNZ's calls.
Mr Li was not to be found at any of his Auckland addresses either.
He is the director of multiple businesses including E and L Construction and also the NZ-China Free Trade Association.
Most of the companies are listed at the same address in Mount Wellington.
But when RNZ went to visit, there was only an employee for a company called NZT Fashions Limited.
The employee told RNZ that Mr Li was the owner but he was not there and did not know when he would next be back.
The Chinese construction workers said they felt lost and disillusioned.
They said they still wanted to work and send money back to their families in China who desperately needed the funds.
For Mr Mao though, all he wants is to get the money he paid to Mr Li back and go home.
"I really can't take this any more. Every day I think about this and I get angry.
"I can't stay here because I can't even provide for my family's daily needs."
Immigration New Zealand (INZ) said it was investigating a complaint against Mr Li.
INZ assistant general manager Peter Devoy said the exploitation of migrant workers was on the rise.
"They are difficult enquiries and they're difficult because there are often language barriers.
"People often come to us after they've been in a position of exploitation for some time. They don't trust authorities [and] they haven't got good support networks in New Zealand."