For years the country's second largest health insurer was being swindled out of hundreds of thousands of dollars by an employee funnelling funds into an account under her dead husband's name.
Nib New Zealand eventually discovered the fraud mid-last year during a routine quality assurance investigation, by which time it had lost more than $333,000 and processed 94 false claims.
One of their own, health cover consultant Asia Laga'aia, was the culprit.
The 61-year-old began working at nib in September 2010 and was in a role where she could process and approve medical claims up to $40,000, pay invoices, and reimburse policy holders.
For the first five years of her nib career she was a trusted employee, and well-loved by her colleagues.
However, court documents released to the Herald show Laga'aia's scheme took root in December 2015 when she found an insurance policy with a similar name to her ill husband, who died the following year.
Laga'aia started by adding her husband's bank account to the policy, which she had access to along with his debit card and pin.
She also established a bogus electronic trial by creating an email address in the original policy holder's name and sending a request to her work email asking for the contact information to be updated.
Shortly thereafter Laga'aia, who was a District Court registrar before working at nib, began fabricating and approving claims on the policy.
Between December 2015 and March last year she made 94 false claims, collecting $333,963.54.
In the first month Laga'aia only made two claims, but after going undetected she was soon filing about a dozen every four weeks and collecting tens of thousands of dollars.
In 2016, she also selected five invoices from a policy holder she had processed a claim for in the past and altered its name and address - before attaching them to her false claims, gaining a total of $9430.
An nib spokesperson told the Herald Laga'aia's fraud was uncovered during a routine quality assurance investigation. She was fired in June last year and the incident reported to police.
Laga'aia briefly denied knowledge of the offending before she began to cooperate with her company and police.
Nib also hired a team to look for other instances of fraud within the firm but found none.
It told the Herald: "We have undertaken a widespread assessment of other claims data and can confirm that no further issues were identified and there was no impact on nib members as a result of this issue."
The insurer said it had since improved its processes and introduced stronger systems to prevent such activity occurring in the future.
Laga'aia, meanwhile, faced prosecution and pleaded guilty to 10 charges of obtaining by deception, two of using a forged document, and a representative charge of accessing a computer system for a dishonest purpose.
An emotional Laga'aia was supported by family in the Auckland District Court on Friday when sentenced by Judge Stephen Bonnar.
She had told police the money was being used to fund her gambling addiction, which the court heard grew "completely out of control" when her late husband fell ill.
Laga'aia also told a pre-sentence report writer the first Covid-19 lockdown last March and April was a "changing point" because it stopped her using pokie machines. She had not gambled since, the court heard.
Judge Bonnar said he was satisfied Laga'aia was genuinely remorseful and her gambling addiction had played a significant role in her offending. However, he said Laga'aia betrayed her colleagues and was not without previous blemishes.
Laga'aia has four previous convictions for using a document for a pecuniary advantage in 1985.
Her lawyer, Joshua Grainger, said Laga'aia felt an obligation to pay back the money she stole after a "fall from grace", but Judge Bonnar said a reparation order was unrealistic.
He added nib was a significant corporate entity which could pursue remedies in the civil courts if it wished.
The judge said the offending was a significant breach of trust and Laga'aia had avoided prison by a "relatively fine margin" - sentencing her to 12 months' home detention.
Serial fraudster Joanne Harrison, who infamously defrauded the Ministry of Transport, was involved in a similar scheme when working as a senior manager at Tower Insurance under the name Joanne Sharp, which resulted in fraud and forgery convictions in 2007.