Only 24% of national roads were described as being in top condition
Almost a third of minor roads have some form of structural damage, according to the first national survey of local and regional roads.
The survey shows that one in three tertiary routes has deep cracks, potholes or disintegration.
Only 24% of national roads were described as being in top condition, with some classified as virtually undriveable.
The survey, carried out for the National Oversight and Audit Commission, found Offaly had the largest amount of structurally deficient roads, with average of 36.4%.
However Offaly also had a high amount (average of 26%) of roads in top condition, with Dublin roads topping that category with 30.6%.
Caroline O'Doherty, reporter with the Irish Examiner, says a large amount of our roads have some structural problems.
"The bigger roads, the regional roads... they reckon about 8% have structural distress," she explained. "With primary roads, you're talking about about 11-17%".
She added that while tertiary roads are 'minor' compared to the two other main categories, they are still used by a large amount of rural dwellers.