Immigration New Zealand says employers across the country are demanding money for jobs in an exploitation scam that preys on the vulnerable.

The cash they request can be as much $50,000.

Do you have information about migrant exploitation? Contact MichaelMorrah@mediaworks.co.nz

An internet café in downtown Auckland has likened the practice to modern slavery.

One worker, who wanted to remain anonymous, claims he was told by his employers to pay $30,000 for a job as a technician. Fearing he might lose his position, he eventually paid out $27,000.

"[It is a] lesson for everyone," he told Newshub. "Don't give the money to any employer. They're not giving you a real job. They don't give you a real wage. They just take your money."

His case is not isolated - Immigration New Zealand says in the last financial year they've received more than 1300 fraud complaints, many of which include a cash for jobs component.

Cash being given for job offers is something that goes on across the country," Immigration New Zealand operations director Peter Elms says.

"It's an underlying problem. It's something we take very seriously."

Almost always, new migrants are the target. The going rate for a job can be up to $50,000.

"It wouldn't surprise me that sort of money was being paid for certain job offers," Mr Elms says.

First Union national organiser Bill Bradford says in his view the practice is modern slavery.

"It's almost forms of slavery or certainly of indentured labour that are taking place."

The anonymous worker says this is how it played out for him.

The internet cafe he worked at was run by Liam Ward at the time.

The worker says a shareholder, Harpreet Singh, demanded $15,000 as a so-called "business investment" and a condition to get the job.

Then, when the business was sold, he says the new buyer, Gautam Savani, requested another $15,000. However, all three of these individuals linked to the business deny these claims.

Once on the job, the worker says he got a little over $6 an hour.

The minimum wage in New Zealand is $15.75 an hour.

Allegations of underpayment are also denied, but there are documents suggesting the worker did indeed hand over two cash payments and wasn't being paid lawfully.

The worker says he came here as a student in 2014 with high hopes.

"I was very excited to get a job and get good money and get a future with my wife. [Now] it's not like the dream. Corruption is everywhere."

Mr Bradford says he deals with one complaint a week about employers demanding cash and underpaying staff.

"It's going on all the timeâ€¦ this sort of behaviour actually undermines the living standards of every person living in this country.

"We, as a country, we can't afford to allow this to continue."

Immigration New Zealand has 20 investigators tasked with looking at exploitation and immigration act offences.

It's assessing whether to formally investigate the case we've highlighted but says it must direct resources to the most serious cases first.

Newshub.