Inland Revenue is warning that it examies all tax credit claims and will catch people filing fradulent paperwork.
The taxman's alert came as a mother who claimed tax credits for three overseas children and a child who was not her own was sentenced to seven months of home detention.
Manukau woman Loata Taufua Patolo has also been ordered to pay $68,000 in reparations for filing false Working for Families, donation and paid parental leave claims.
Patolo pleaded guilty to charges under the Tax Administration and Crimes Acts of falsely claiming the refunds, and of attempting to claim a further $31,000.
Her offending occurred between 2006 and 2011, Inland Revenue's group manager assurance Patrick Goggin said.
''During this period, Patolo received Working for Families tax credits for her three children, even though they had all left the country in early 2007 and are still overseas,'' he said.
''She also applied for tax credits for an additional child in her care, to which she was not entitled, and filed using other peoples' names and false details.''
Patolo also claimed donation tax credits, both in her own name and her partner's name, along with false paid parental leave credits using forged medical certificates and by telling Inland Revenue that she was self-employed, Goggin said.
''This was a deliberate and concerted effort to obtain money from Inland Revenue. Patolo clearly understood the tax rules, because not only did she file a number of false claims, but she also filed in three different tax types.
''Our staff became aware of the offending when our investigation showed that the refunds, including those claimed for different people, had been paid into Patolo's bank account.
''This case is a reminder that Inland Revenue examines all tax credit claims and the organisation is using its resources and techniques to catch those making fraudulent claims.
''No matter how much effort, time, and even money a person spends trying to avoid paying tax, or claim money illegally, they will be caught in the end,'' Goggin said.