Ani, who is married to a New Zealander, was arrested in August 2010 as part of a wider Immigration NZ inquiry, code-named Operation Naira.
The wide-ranging probe reviewed 160 cases and exposed the problems New Zealand authorities face combating immigration fraud.
More than 40 residency applications were declined.
Four men have been convicted, most recently Remi Eme Chukwu, who was sentenced last month to 11 months of home detention.
One of the men jailed, Chidozie Emmanuel Onovo, was working as a hospital psychiatrist in Christchurch when he was found to have falsified documents to hide a British drug-smuggling conviction.
Another, Hakeem Amoo Ewebiyi, was working with sex offenders for a community health provider when he was discovered to have entered NZ on a false South African passport.
A third, Jeffrey Ugochukwu Orji, is an engineer who unsuccessfully sought refugee status in New Zealand 10 years ago before returning on a false passport a year later.
The 43 declined residency applications are mostly family members of those charged, relatives who tried to gain permanent access through the secondary migration policy.
The cost savings from preventing fraudulent secondary migration are significant.
"It has been estimated that on average each refugee fraud conservatively costs the Department of Labour $28,550," says a 2010 report.
This does not include the "downstream" cost to the taxpayer of legal aid, healthcare, education, state housing, welfare, police and courts.
While Operation Naira was successful in stopping others from being granted residency, the investigation also raised questions over the adequacy of the vetting system.
The sweeping inquiry came soon after an Auditor-General's report in 2007 criticised Labour Department handling of identity fraud detection and highlighted the inadequacy of risk identification at the time.
The Auditor-General made 15 recommendations, all of which the Minister of Immigration ordered to be implemented.
These included the need to identify, monitor and address risks specific to immigration fraud and greater training for frontline staff assessing applications to detect dishonesty.
Sophisticated passport scanners to detect forgeries have since been introduced at airports, as well as pre-screening processes which have decreased asylum claims from a peak of 2000 each year to 300.
In focus
Name: Anthony Okechukwu Ani
Age: 56
Charges: 13 under Immigration Act
Secondary migration: Tried to bring 10 children into New Zealand
Pleaded: Not guilty.
