A leading Irish conservation group has called on Iarnród Éireann to speed up repairs to the collapsed railway bridge outside Malahide in order to protect birds migrating to the area in the coming weeks.

BirdWatch Ireland says it is "extremely concerned"about the recent collapse of the railway viaduct over the Malahide estuary, a site of international importance for wintering wild birds, which is designated as a special protection area under the EU birds directive.

In an interview with the Sunday Tribune, Niall Hatch, development officer with BirdWatch Ireland, said: "It is imperative that this railway embankment is put back as quickly as possible. The reason for this is that the water levels of the inner estuary at Malahide do not drain completely at low tide, creating the ideal living and feeding conditions for certain protected birds. These conditions have largely been maintained by the railway embankment, which has served in the past to restrict the water flow. In the coming weeks we will have birds arriving on Malahide estuary – they will come back expecting to find the deep water they need to dive in and they could be adversely affected by the drop in water levels."

These protected birds include Goldeneye and Red-breasted Merganser ducks, as well as Brent geese who come from Arctic Canada to Malahide estuary each year, one of the very few locations around Dublin that supports high numbers of diving waterfowl species.

"It is vital that the water regime be returned to its original state when reconstruction activities take place, and we will be recommending that this happen as soon as possible," Hatch said. "We hope to work with Iarnród Éireann, local community groups and the National Parks and Wildlife Service to ensure that the benefits of this important site to wildlife and people are not lost."

Iarnród Éireann spokesman Barry Kenny said the company was "very aware"of the bird life in the area around the collapsed railway bridge and was doing all it could to restore water levels at Malahide estuary.

"The primary purpose of the work is to rebuild this causeway area which provides protection for the other piers. That is designed to ensure normal flows in and out of the estuary are also protected and which would ensure that the environment for the birds is maintained. Whereas our primary focus is on ensuring that we rebuild this causeway and protect the other piers, it will also ensure that the status quo in terms of the water flow in and out of the estuary is protected and that will ensure that the environment for the birds is maintained."

Iarnród Éireann says it stands by its assessment that repairs to the railway viaduct would be completed within three months. "There are a lot of engineers coming out and saying different things but the only people who are actually qualified to say how long the job is going to take are the people who are on site and can see what they're dealing with. Three months is our engineer's best estimate at the moment; as we move along on this, we will be able to firm that up but that is the timescale," said Kenny.