Potential overpayments for maintenance work were not identified by the Northern Ireland Housing Executive because of a lax approach based on trust, an audit office report said.
Normal contract management arrangements were set aside in favour of more relaxed procedures which meant effective checking was not carried out, the audit office reported. Potential overpayments on kitchen replacement schemes totalled £1.3 million in a sample reviewed by external surveyors.
Comptroller and Auditor General Kieran Donnelly qualified his opinion on the 2012/13 accounts because of significant problems in the contract management of maintenance and the estimated level of fraud and error in housing benefit payments.
"The assessment by the external surveyors found that, in general, normal contract management arrangements had been set aside in favour of more relaxed procedures based on partnership, trust and mutual co-operation which meant that effective checking and inspection was not being carried out and consequently potential overpayments were not identified," he said.
External surveyors on a sample of 20 kitchen replacement schemes (out of a total of 242 schemes undertaken to date) found potential overpayments of £1.3 million out of a total cost for all schemes examined of £6.2 million. The potential total contractor overpayment since 2008 is estimated at around £18 million.
The auditor said: "I am very concerned that the Housing Executive's seemingly lax controls appear to have resulted in such a large potential loss of public money. I am also disappointed that these issues were not addressed earlier."
He said that could have been in 2010 or 2011. He added: "Unfortunately there was a considerable degree of challenge by Housing Executive management to the findings of CAU (Corporate Assurance Unit) which delayed the appointment of external surveyors until late 2012."
The Executive told him its intention is to seek full repayment of all overpayments made to contractors and a legal recovery strategy, approved by the board, has been implemented. The first step of this has involved formal adjudications based on the independent evidence prepared by the external surveyors but further legal action cannot be ruled out.
The Executive told the auditor it has already put in place improved controls and arrangements addressing weaknesses and behaviours which allowed the overcharging.
These include increasing the number of professional officers available to inspect and pass work for payment, retraining relevant staff to stress the need for effective checking and monitoring of schemes, and the establishment of a Central Cost Group to provide an additional layer of scrutiny and certification of claims for payment submitted by contractors.