THE Railway Procurement Agency has warned that the proposed €750m redevelopment of Arnott's department store could lead to an increase in traffic accidents involving Luas and cars.
The RPA has also warned An Bord Pleanala of a "significantly increased" possibility that delays to services will occur because of car-parking arrangements in the proposed Northern Quarter scheme.
An Post has also objected to the plans, saying that elements of the proposal for Dublin's north inner city would effectively put the GPO "beyond reasonable use".
The concerns are included in eight objections sent to the board after Dublin City Council granted planning permission for the project last month.
It is proposed to create a new shopping, entertainment and residential zone on a 5.5-acre site, and the objections raised relate to building height and design and the impact five years of construction would have on businesses.
The buildings range in size from three to 12 storeys, with a 15-storey tower at the corner of Abbey Street and Liffey Street.
In a letter to the board, the RPA says it was "denied its right" as a public body to comment on Arnott's plans.
It argues that a decision to include access and egress to the development's car park via Middle Abbey Street, instead of via an alternative access point at O'Connell Street, was a "material change" and it should have been consulted.
It also says that over 600 car parking spaces would be in close proximity to "perhaps the greatest concentration of public transport services in the State" and that the new quarter should encourage people to use buses and Luas.
If the sole means of accessing Arnott's is via Abbey Street, it warns: "The potential for delays to trams is significantly increased and the level of service for tram operations substantially diminished.
"The provision of a carpark entry off Middle Abbey Street in addition to an exit at the same location, coupled with increases in usage, will lead to delays for road traffic. RPA is gravely concerned that the effect of these delays will be such as to encourage driver misbehaviour at the car park access location, with the potential for conflict with Luas trams."
The agency said yesterday it had submitted observations because of its concern about the car park, and because this conflicted with government policy to take cars off the streets.
"The provision of car parking has gone up, and that's a conflict with removing cars off the streets," a spokesman said. "We're carrying one fifth of what Dublin Bus carries with 26m passengers, and that points to a real need to keep the priority going for Luas."
An Post says plans for a "new" Prince's Street with service entrances would encroach on its property and "effectively put the An Post building beyond reasonable use". An Bord Pleanala will decide by December if the scheme will be granted permission.