Fraud and error has cost the public purse in Northern Ireland £24 million, it has been revealed.
Housing benefit, rates and pensions were targeted by fraudsters while concessionary travel passes and disabled parking badges for dead people were still being used, said the Northern Ireland Audit Office.
The deception was uncovered over the last two years as part of a crackdown on fraud which matches data held by public bodies with files like death records.
Auditor General Kieran Donnelly said: "These powers have strengthened considerably the hand of the public sector to combat fraud."
The initiative compares data like payrolls, pensions and trade creditors' records against other information held by the same or different organisation to determine whether the recipients of payments are eligible.
For example, payrolls between different employers can be compared to catch employees working elsewhere while on sick leave.
Housing benefit payments can be compared to payroll to discover if claimants are not declaring income which may remove their entitlement to benefit.
Pensioners receiving housing benefit may not be declaring their full pension income. Pensions may be paid to a pensioner who had died but whose relatives fail to notify the fund's administrator.
The report found that about 70% of fraud and error identified by the National Fraud Initiative (NFI) in Northern Ireland is being recovered.
Mr Donnelly said: "Public bodies are encouraged to spend to save and to recognise the contribution that their participation in the NFI can make to the interests of Northern Ireland as a whole."