A combination of mistakes, technical errors and fraud has cost the Northern Ireland taxpayer 24 million, according to the Northern Ireland Audit Office said.
Housing benefit, rates and pensions were targeted by fraudsters while concessionary travel passes and disabled parking badges for dead people were still being used, the NIAO said.
The key findings of its report are:
- Between April 2010 and March 2012, housing benefit fraud and overpayment amounted to just over £4 million and several high-value prosecutions were secured;
- For the same period, more than £13 million of rates evasion and error were identified in domestic rates. Almost 500 cases of rates evasion were discovered;
- Suspected fraud, error and overpayment of pension payments amounted to more than £2 million;
- The matching of blue badge (disabled parking) holder records to death records resulted in more than 7,000 matches;
- There were more than 15,000 matches between concessionary travel pass holders and death records. Some 14,000 of these passes had been cancelled by the end of March this year;
- £387,000 was overpaid to suppliers;
- About 70% of fraud and error identified by the National Fraud Initiative (NFI) in Northern Ireland is being recovered.
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 said some bodies still needed to include the initiative more in their counter-fraud strategies. It added there should be greater publicity of successful prosecutions to deter potential fraudsters.
Mr Donnelly said: "The results clearly demonstrate the value of data-matching as an effective counter-fraud tool.
"This is good news at a time when public resources are particularly stretched.
"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.
A DRD spokesperson said: “Translink has been proactive in dealing with matches and the deactivation of passes of deceased pass holders.
“It is not a case that smart passes were issued to deceased individuals. Rather, there will always be a proportion of travel pass holders who regrettably pass away. The NFI match has generally arisen because their dependants have simply not realised that the passes should be returned for cancellation.
“There was minimal evidence that cards that should have been cancelled were actually in use reflecting the long established controls in place for the use of Smart passes.”