Dún-Laoghaire Rathdown County Council has ordered that a newly built cycle lane be ripped up and replaced because it is too narrow.
Work began yesterday on breaking up the new lane, south of Foxrock Church on the outskirts of Dublin city, which had just been completed as part of a multimillion euro upgrade of the N11.
Construction workers have spent the last 12 months putting in a new bus corridor and cycle lane on the road between Foxrock and Shankill. The scheme is not yet complete.
Yesterday senior staff at the council confirmed it had to remove part of the cycle lane, which adjoins the footpath, on the south-bound carriageway when it was found to be 60 centimetres too narrow.
The work includes the removal of a large concrete kerb-like wall that was built to bank up the front gardens of houses adjoining the cycle path.
The problem was identified during an inspection of works last Thursday, according to the council, which said it wanted to rectify the problem immediately.
Mr Tony Pollins, a senior executive engineer with the council, said the current width made it dangerous for pedestrians and cyclists.
"Yes we should have spotted it earlier, but now we are trying to make it safe as quickly as possible," he said. "It's unfortunate but these things sometimes happen. Civil engineering is not a perfect science."
The cost of the work is still unknown, according to Mr Pollins, who said it had yet to be established whether the council or the contractor was financially responsible.
He said the priority was to ensure that the lane was safe to use.