The boss of an Auckland building company charged with immigration fraud lives in a $2.3m home and drives a late model Porsche.

Hooi Keat Chai faces 26 charges of lying to immigration officials over 12 years to get fraudulent visas to study and work in New Zealand, eventually being granted permanent residency.

This is because Immigration New Zealand alleges the 34-year-old previously lived in New Zealand unlawfully under the name Kok Tong Chai but changed his name in Malaysia and then returned under the new identity.

His home in the affluent Auckland suburb of St Johns was raided by INZ investigators this week and Chai, who introduces himself as Ben, became the second individual charged in Operation Spectrum.

Read more:
• Inside Auckland's construction jobs
• Operation Spectrum stops nearly 200 illegal workers

The Weekend Herald last week revealed nearly 200 illegal workers were either deported, fled New Zealand or stopped at the border following the six-month inquiry into the construction industry in Auckland.

Chai is the sole director and shareholder of Team NZ Constructions Ltd, one of the 10 companies targeted by INZ in a bid to disrupt the flow of illegal workers from Malaysia.

Operation Spectrum also uncovered a weakness in border security whereby 15 people previously deported or who fled from New Zealand were able to return under new identities.

Chai is one of two individuals who allegedly went to obtain permanent residency.

He was charged in the Auckland District Court on Friday and bailed to his $2.3m home, where 5 vehicles - including a 2017 Porsche Cayenne - are registered in his name on finance records.

Operation Spectrum targeted companies which recruited unlawful workers from Malaysia as plasterers, painters, tilers or carpenters.

They worked as third-tier subcontractors, below the radar of developers and site managers.

There was little evidence of workers living in poor conditions, or being exploited against their will.

Most were paid just $20 to $40 an hour in cash - paying no tax - so those running the underground crews were able to win contracts by undercutting the prices of legitimate competitors.

"It was common to hear 'we got paid every Thursday by a man in a black Audi'," said Alistair Murray, who manages investigations and compliance for INZ.

"We are talking significant cash flow, hundreds of thousands of dollars.

"So Kiwis are being cut out of jobs. Legitimate Kiwi businesses trying to contract in that market can't compete with those rates. It's not a level playing field."

Immigration New Zealand raided construction sites around Auckland and detained and deported 54 people.

On one occasion, at least 20 illegal workers fled and scattered through the streets of Mt Wellington.

"They just scarpered, disappeared when we turned up," said Murray.

"Even on the most simple of sites, it was a massive exercise to do a floor-by-floor sweep with two people blocking each exit. We'd find people hiding in fire exits, stairwells, ceiling cavities.

"Or sometimes they were in the middle of plastering a wall and we'd tap them on the shoulder to say: 'You've been here unlawfully for 10 years, time to go home'."

Another 36 people fled the country before they were caught, while 15 who had visas to live in New Zealand - but not to work - were served with deportation liability notices.

On average, the 105 people had each lived here unlawfully for five years.

One had been here for two decades.

"They're living here, enjoying the benefits of New Zealand, cutting legitimate businesses out of work. And not one of them paying tax," Murray said.

The Inland Revenue Department said investigations were ongoing.

Another 85 would-be illegal workers were stopped at the New Zealand border, or sometimes before they stepped foot on the plane to carry them here.

In total, 190 people were stopped over a six-month period.

Out of those, Operation Spectrum uncovered 15 who had previously been deported, or fled New Zealand before they were caught but returned under a new identity.

"The ability of someone to be deported, change identity, and be back quickly is a concern, because we don't know who is here," Murray said.

The improved collection of biometric data, such as fingerprints, facial recognition software and database checks by Immigration NZ staff meant more dual identities were detected now, Murray said.

Last week, one of the Malaysian nationals caught in Operation Spectrum narrowly avoided going to prison.

Adam Gan Bin Abdullah, a builder, was deported from New Zealand in 2012 under his previous name of Meng Kuang Gan.

The 39-year-old changed his name in Malaysia after marrying a Muslim woman, as is the custom, and returned to New Zealand the following year.

Abdullah repeatedly failed to declare his previous name or deportation, eventually obtaining permanent residency here until being caught in Operation Spectrum.

He pleaded guilty to immigration fraud charges and by a "fine margin", Judge John Bergseng decided to impose a sentence of 10 months' home detention instead of prison.

"Truthful declarations are the cornerstone of the New Zealand immigration system. Your offending directly challenged this," Judge Bergseng said in the Manukau District Court.

"You had a deliberate plan to deceive. This was clearly premeditated, fraudulent and repeated. Having been successful once, you thought you'd get away with it again."