There are concerns about delays to the planned MetroLink because of a number of submissions.
A number of state agencies have lodged concerns including the Office of Public Works.
It's concerned about the impact of one of the stops on Stephen's Green and its links to 1916.
But Labour's Transport Spokesperson Duncan Smith says he doesn't understand that.
He said: "Quite frankly I found the 1916 reference as it relates to MetroLink quite head scratching given where the plan design is for the station.
"It wouldn't have any impact on the 1916 area of St. Stephen's Green, so that's something that I quite plainly don't understand."
Sinn Fein says it's disappointing and frustrating that there could be further delays.
Construction is meant to start in 2025 but it needs permission from an Bord Pleanala.
Transport Spokesperson Martin Kenny says it can't afford any more set backs.
He said: "Every aspect of this from it's very concept to it's delivery has been marred with delay after delay after delay, so to see the prospect of another delay is very disappointing.
"Certainly disappointing for people who bought houses out around Swords 20 years ago expecting to have a metro going past them to bring them into Dublin four to five years after that.
"And here we are 20 years later."
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