Just one fake marriage has been prosecuted in the past 18 months despite nearly 10 "tip-offs" every month.
The Hamilton man, referred to as 'A', gained permanent residency in 2005 after telling Immigration officials that 'C' was his de facto partner. He was subsequently granted New Zealand citizenship and then married 'B' in May 2008 and sponsored her visa application.
The man also gave her a job at his business in Hamilton. But the sham marriage was sprung when Immigration staff made a surprise visit to verify the relationship.
'A' was found to be living with his original partner 'C' while his "wife" was living in another part of Hamilton. He admitted he had never left 'C' and only married 'B' to help her gain residency. The immigration application failed when the fraud was exposed and she left the country.
'A' pleaded guilty to three charges of giving false information to an Immigration officer and was sentenced to 260 hours of community work in December last year.
The case details were released under the Official Information Act but Immigration New Zealand withheld the names and other identifying features to protect their "privacy".
The Herald asked for the information after revealing a West African drug dealer married a New Zealand woman to help him get residency.
Sylver Dube, 35, came here on a visitor's visa in March 2009 and met Auckland woman Tihere Ford a few weeks later. The pair wed in Manukau on July 24, 2009. Dube, born in South Africa but brought up in Nigeria, was arrested in February 2010 and faced more than 80 methamphetamine charges. After his arrest, Ms Ford told police they did not live together but he paid her $100 a week for board.
The arrangement was to help him with his immigration into the country.
She later gave evidence against him at trial, where their marriage was described as a "sham".
The couple agreed in court that Dube stayed in Ms Ford's home only two or three nights a week, and shared a room with her teenage son.
Dube then used his stepson to send money to Nigeria and South Africa through Western Union transfers. He was found guilty and was sentenced to 15 years in jail.
No charges were laid over the fake marriage. The figures released by Immigration New Zealand show that 177 allegations of marriage or partnership fraud have been made in the past 18 months, nearly 10 each month.
The fraud branch investigates each allegation as a preliminary inquiry with three outcomes: insufficient evidence so the case is closed, referred to another Immigration branch to manage the case, or escalated to full investigation.
Of the 177 cases, 123 were closed early - 70 per cent - and a further 47 were transferred internally. Three were still at the preliminary stage and four had been escalated to a full inquiry.
Two intelligence reports about sham marriages were withheld by Immigration on the grounds that release would "prejudice the security and defence of New Zealand or the international relations of the Government" as well as "the maintenance of the law".
Files in the past 18 months
• 177 fraud allegations
• 123 cases closed
• 47 transferred
• 4 full investigations
• 3 preliminary inquiries
• 1 prosecution