The new €60m bridge over the River Liffey has had bus lanes put in place even though no bus routes will use it.

Two of the bridge's four lanes have been given over to public transport despite the fact there is no plan to run any bus route across it.

The Samuel Beckett Bridge has already been criticised by motorists, who complained about difficulties in navigating a complicated series of right or left turns.

Traffic snarl-ups of more than 15 minutes have already become common in both directions from the bridge, with bans on turning away from the bridge infuriating drivers.

Difficulties in traffic flow are likely to discourage any bus operators from using the new crossing while the bus lanes vanish on both sides of the Liffey as soon as a vehicle leaves the bridge.

Dublin City Council said a bus lane had been provided on the bridge to facilitate the "future provision" of buses in the Docklands area of the city.

It said: "[The area has] undergone significant regeneration over the past 12 years, which has seen the population grow there from 17,500 in 1997 to 22,000 in 2008.

"Also, the bridge is intended to facilitate the orbital route traversing the city from north to south and vice-versa so the bus lanes will facilitate future bus-provision on this route."

The council also said the primary reason for a ban on many right and left turns was to discourage users of the East Link toll bridge from diverting.

It said that as part of the planning process, An Bord Pleanála had only granted permission on condition there was "no right turn" in both directions off the bridge and "no left turn" onto the bridge from North Wall Quay.

A statement said: "Dublin City Council implemented the 'no right turn' and 'no left turn' in accordance with the conditions imposed with the planning permission granted by An Bord Pleanála.

"The bridge was intended to facilitate the orbital route traversing the city from north to south and vice-versa. It was never intended that traffic which uses the Eastlink daily would divert onto the bridge.

"This would increase the volume of traffic in the south east inner city and adversely affect the residents there considerably."

The bridge is designed on a massive pivot, which allows it to turn sideways, to allow access for ships or other vessels wishing to move up the River Liffey.