The Labour Party TD and councillor, Mr Eamon Gilmore, is to ask Dun Laoghaire-Rathdown County Council to examine the worsening erosion along the rail line at Dalkey, Co Dublin.
Mr Gilmore said while significant work was done in the area in recent years, a safety issue could arise if erosion was allowed to worsen.
During the Christmas holidays a large chunk of earth on an embankment at the back of the White Rock area of Killiney beach was washed away by the sea. The erosion has steadily crept up the embankment towards the rail line which carries the DART service and Dublin-Rosslare mainline traffic.
It is understood that an Iarnrod Eireann team has been maintaining the area and has attempted to prevent further erosion by dumping hundreds of railway sleepers into the eroded hollow. The sleepers failed to prevent the latest slippage, and many of them are now lying among rocks on the beach.
Other parts of the embankment eroded by waves have been cemented over by workers.
The erosion appears to have been caused by a hole in the wall protecting the embankment. This wall is collapsing and is being held up by two metal devices. The area was cordoned off when The Irish Times visited the site yesterday.
When the sea at White Rock is rough waves crash through the holes in the wall and drag the soil away. Local people at the site yesterday wanted the wall permanently sealed. Mr Pat Keegan, who regularly jogs past the area, said the safety of the rail line could be threatened if something was not done soon.
"There are people working on this area all the time, but nothing permanent has been done about it. Instead of putting bits of cement here and there, the whole area should be reinforced and that would stop the problem once and for all," he said.
Another local man, who did not wish to be named, said the embankment in many places looked unstable and earth was constantly falling away. "A lot of the heavier trains that run along the line seem to be causing a lot of strain," he added.
Protection of the coastline is the overall responsibility of the Department of the Marine, but local authorities are charged with carrying out works in beach areas.