DECADES of underfunding is causing Northern Ireland's road network to seriously deteriorate, a report has found.
The Audit Office said £50 million extra is needed every year to maintain the north's roads in a "steady and sustainable state".
And it revealed there is a £1.2 billion maintenance backlog.
Comptroller and auditor general Kieran Donnelly said a strategy is needed along with a long-term funding plan to protect "a key public asset".
The report, Structural Maintenance of the Road Network, highlights that while major roads such as motorways are in a better condition than previously thought, minor roads, including much of the rural network, are getting worse.
In Northern Ireland 78 per cent of the network is classed as rural, with 22 per cent urban roads.
Over the past five years an average of £92m has been spent annually on structural maintenance but it is estimated the funding required is £143m.
The report also highlights that the Department for Infrastructure relies heavily on 'late-in-year' funding, reducing its ability to plan ahead.
Mr Donnelly said one of the surprising findings was the absence of a roads maintenance strategy.
Recommendations for the department include securing long-term funding options, such as ring-fenced funding, and to reconsider how money is allocated to ensure fair coverage for all sections of the network.
The report finds that while the road network is of "significant economic and social importance" and the number of vehicles using the roads is growing significantly, the total distance travelled is not.
The major cause of wear and tear is the damage done to road foundations and pavements by heavy goods vehicle (HGV) traffic.
It points out that motorways and trunk roads are structurally more resistant but smaller and older roads are more prone to structural failure arising from the weight or volume of modern lorries.
The findings also detail that long-term deterioration of the road network increases the risk to public safety and that "while small in number, the impact on the individuals and families involved in such collisions can be significant, as can the direct and indirect socio-economic costs of such collisions".
A spokesperson for the Department for Infrastructure welcomed the findings and said it will work with the Department of Finance to see what measures can be put in place to address the issues raised.
Angela McGowan, director of the Confederation of British Industry NI, said it has long highlighted the strong correlation between good infrastructure, higher productivity and economic growth.
"For the business community, poor road maintenance translates into increased risk of accidents, greater wear and tear of vehicles and increased journey times for workers, as well as deliveries of supplies and end-product," she said.
Sinn Féin's Philip McGuigan said that "after years of austerity imposed by the British government it is disappointing but not surprising that £1.2bn of funding is needed to restore our roads to a decent standard".
The UUP's John Stewart MLA said the report should act as a call to action for political parties to come together and agree a long-term "national infrastructure programme".
