The idea of completing the Dublin Metro by 2027 has been labelled as "farcical" by one Fianna Fáil TD.
€3bn will be spent on the line which will extend from Swords to Sandyford.
That will be developed in tandem with an extension to the DART, with both projects aiming to be open to passengers within a decade.
But Deputy Darragh O'Brien is worried such a large undertaking will not meet its deadline.
He said: "Unfortunately, what that means to me is that we are going to be waiting even longer, no one actually believes it is a priority.
"We really need to see boots on the ground and the project started.
"This idea that it will be up and running in 2027 is actually farcical and no one actually believes it."
- Digital Desk