Fraud and error resulted in excess of £90 million worth of benefits being overpaid in Northern Ireland last year, auditors have found.
Official mistakes also saw around £25 million of underpayments, according to the report by the Northern Ireland Audit Office (NIAO).
The figures were contained in the NIAO's annual assessment of the accounts of government departments and other public sector bodies.
Auditor general Kieran Donnelly placed "qualifications" on a total of 20 accounts to indicate a variety of weaknesses in financial control.
The Department of Social Development overpaid £71.9 million due to fraud and error while it recorded £20.8 million of underpayments due to official error.
DSD paid out a total of £5.5 billion in benefits in 2013, so overpayments accounted for 1.3% - the same rate as 2012 - and underpayments rose slightly to 0.4% from the 0.3% level the year before.
The overall 1.7% rate of over and underpayments was lower than the 3% in the Department of Work and Pensions in England.
In the Northern Ireland Housing Executive's administration of £659 million of Housing Benefit, there were £21.1 million of irregular overpayments and £4.8 million underpaid - equating to 3.2% overpayment rate and 0.7% underpayment.
In respect of the NIHE Mr Donnelly found weaknesses in controls over £41 million of response maintenance and £86 million of planned maintenance work.
Three public bodies - the Department of Health, the Department of Education and the Public Prosecution Service - saw their accounts qualified after they broke their annual expenditure limits.
Meanwhile, the Department of Culture, Arts and Leisure, Office of the First Minister and Deputy First Minister and the Department of Employment and Learning all incurred significant expenditure without the necessary sign-off of the Department of Finance.
Mr Donnelly said: "The standards of financial accounting remain high, demonstrated by the quality and timeliness of the financial reporting. However my report records the qualification of 20 accounts."