There are concerns about fresh delays to the planned MetroLink in Dublin.
The major transport infrastructure project is still waiting for planning permission and submissions to an Bord Pleanála could threaten this.
A number have been lodged over concerns about MetroLink's design and the location of a proposed stop at Stephen's Green.
According to freedom of information requests from the Daily Mail the DAA, the Office of Public Works and the National Parks and Wildlife Service are among those raising concerns.
A senior transport official has described the submissions as unhelpful - leading to concerns construction on MetroLink could be delayed.
The long-awaited rail project, which will connect Dublin airport with the city, is at the heart of the Government's 2040 Project Ireland and transport plans.