Business network Dublin Chamber is calling on the Government to introduce emergency legislation to ensure that MetroLink "proceeds without further delay".
It comes after it emerged yesterday that a group of residents in Ranelagh have begun a legal challenge against the planned rail line for the capital.
The residents have applied to take a judicial review of the decision to give the green light to the MetroLink project.
The project would see the construction of an 18.8km railway line, most of which will be underground, from Charlemont near Dublin city centre to Swords Estuary in the north of the county.
Twenty people are named in the application from the judicial review, many of them residents of Dartmouth Square off Leeson Street, which is located close to the planned final stop for MetroLink.
Dublin Chamber said the economic well-being of the entire Dublin region is threatened by what it described as the "latest attempts to derail MetroLink through judicial review submissions".
The business group says the Government "must now step in decisively".
The President of Dublin Chamber said the State has "stepped in before to unlock vital infrastructure, and it must do so again".
Eoghan Quigley said the MetroLink is "a once-in-a-generation project and allowing it to be held up by serial objections and procedural games is unacceptable".
"When national progress is being blocked, Government has a responsibility to act."
Dublin Chamber said it has warned that "continued obstruction is already damaging confidence in Ireland's ability to deliver major infrastructure, pushing investment away and weakening Dublin’s international competitiveness".
The Chamber President said Dublin "cannot be paralysed by never-ending legal obstacles".
"We need emergency legislation to ensure that projects of national importance are not unduly delayed, and we need it immediately."
