All costs incurred as a result of last year's Westlink flooding in Belfast should be identified and potential to recoup them investigated, an audit report has said.
The road was at one point under 20 feet of water during flooding in August 2008.
A report from comptroller and general Kieran Donnelly said the Department for Regional Development should recoup money from the consortium behind the building of the multi-million pounds Broadway underpass - indemnified or public liability costs.
Other costs incurred which are not indemnified should also be identified and the potential to recoup those costs should be investigated, the report added.
"Similar costs incurred by the other public sector organisations, for example costs to emergency services, should be identified by those organisations and the potential to recoup those costs should also be investigated," it said.
Westlink builder Highway Management Construction has said a design fault was not to blame for the flooding. It pointed to the unusual conditions and said to get a month or three-quarters of a month's rain in 12 hours was exceptional rainfall.
'Exceptional rainfall'
An independent report providing recommendations for safety cost the Department £58,000. A hydraulic model examining the complexities of the drainage system came to £70,000 and is to be shared equally by the Roads Service, Rivers Agency and the consortium.
A Public Private Partnership was used for the Westlink upgrade.
The audit report, 'Improving the Strategic Roads Network- The M1/Westlink and M2 Improvement Schemes', said other significant costs including the economic impact of the road's unavailability while the flooding was resolved were incurred.
The contract does not repay other public organisations for loss.
It also included sliproads on the M2 at the Antrim Hospital, widening of the M2 from the Sandyknowles to Greencastle junctions and network maintenance over a 30-year period.
It cost £186 million compared to £250 million calculated by the Department for delivering the schemes through the conventional route.
Work began on the Westlink in January 2006 and the final phase was completed in May this year, three months ahead of schedule. Financing for the project included sums from the European Investment Bank and the use of index-linked bonds, a first for Northern Ireland.
© Press Association