The stadium's west stand runs directly over railway lines which carry Dart services and intercity trains between Dublin and Rosslare port, which must be closed temporarily to allow the stand to be demolished.

A senior source at CIE expressed surprise that planning permission had been granted in absence of the agreement.

However, the Lansdowne Road Stadium Development Company (LRSDC), the joint venture set up by the IRFU and the FAI to redevelop the stadium, had yet to agree an acceptable programme of closures with Iarnrod Eireann.

The LRSDC plans to close the line for 11 days across three bank holiday weekends to carry out the demolition work, with an additional 15 nights of work above the line.

However, Iarnrod Eireann has told the LRSDC that it will only close the line for two bank holiday weekends. A spokeswoman added, "No night working has been agreed with the LRSDC and, if necessary, this will be discussed on a case by case basis, under the strict proviso that no services will be affected."

It has also emerged that the issue may be further complicated by planning conditions imposed on the redevelopment by An Bord Pleanala regarding when work can be carried out on the site.

The conditions state that, unless the LRSDC secures special permission from the planning authorities, demolition work can only occur between 7am and 6pm on weekdays and 8am and 2pm on Saturdays.

However, an Iarnrod Eireann spokeswoman said it would "only permit work to take place during periods of 'special permission'".

Iarnrod Eireann may also seek a financial contribution from the LRSDC towards the redevelopment of Grand Canal Dock and Sandymount Dart stations, which may have to be upgraded to handle additional spectators attending matches at the rebuilt stadium.

A spokesman for the LRSDC said it had been in detailed technical discussions with Iarnrod Eireann for the past 12 months involving specialist consultants on both sides. "The LRSDC appointed a railway-demolition contractor early so they could take part in these discussions, " he said. The company hopes to have the stadium completed by the end of 2009.