It comes as ministers prepare to sign off on the next stage of the project this morning (16 September).
The cost of building a Metro in Dublin is expected to be much higher than previously estimated.
It comes as ministers prepare to sign off on the next stage of the project this morning.
The last estimate for Metrolink, back in 2022, put the cost at around €9.5 billion.
But that's risen sharply with the final bill for the underground rail line, running from Swords to the city centre, now predicted at between 14.5 and €17.5 billion.
This morning Transport Minister Darragh O'Brien will look for cabinet approval for the project to be put out to tender.
After this, bids will be accepted for the construction of MetroLink.
Minister O'Brien will tell his colleagues the project will then move to procurement, with work on the ground to begin next year.

Central Bank Reveals Average Time Of Four Years To Build House
Man Dies Following Two-Vehicle Collision On M4 In Enfield
Irish Rugby Legend Sets Off On Kildare Leg Of Nine-Marathon Charity Event
The 95th Edition Of The National Ploughing Championships Gets Underway This Morning
Occupied Territories Bill Comes Into Effect
EU To Propose Social Media Restrictions For Under 15s
Revolut Scammed After Passing On Data To "Unauthorised Third Party"
"Westminster's Time Is Coming To An End": SF, SNP, And Plaid Cyrmu Call On British Government For Constitutional Change