The Transport Minister has accused people who go to the courts to try and block major infrastructural projects of robbing money from tax payers.
Martin Cullen said if there was a lesson from the M50 it was that once proper independent procedures had been completed that should be it.
He said he wanted to see an end to people going to the courts after that time.
Mr Cullen was speaking at the official ceremony of the opening of the final South Eastern section of the M50.
Ballooning land prices and legal wrangles over the remains of the medieval Carrickmines Castle have contributed to a completion cost of €570m - far above the original estimate.
The 10.1km stretch of motorway, which has four interchanges and 18 bridges, was opened to motorists at 4pm. All 40km of the M50 is now navigable.
However, the slip roads off the Carrickmines roundabout will not be accessible to traffic until a later date.
While there will be celebrations, rows are continuing over why an idea conceived 34 years ago only reached construction stage 17 years later and was completed today at a vastly inflated price.
The National Roads Authority says land prices and legal costs are responsible, but opposition parties have accused the Coalition Government of gross mismanagement in its failure to stem the over-runs.
