Plans for the College Green plaza in the city centre have been delayed.
A decision on whether or not the 10 million euro civic plaza can go ahead won't be known until April at the earliest.
The council applied to An Bord Pleanála last May for permission to build the pedestrian and cyclist only plaza - which would ban all traffic to and from Dame Street.
The delay means the council will not be able to stop buses crossing College Green ahead of the start of operations of the new Cross City Luas line in December.
When it made its application to the board last May, the council said the plaza was expected to take up to 18 months to construct, and would not be in place ahead of the start of operations of the line.
However, it said if the board granted permission as expected by November, it would be in a position to implement the traffic changes immediately, before building the plaza.