The European Investment Bank (EIB) has agreed in principle to grant €500m ($752m) for the Dublin Metro project in Ireland.
If approved, this will account for 8% of the project's estimated €6bn ($9bn) cost, according to herald.ie.
The metro scheme, seen as a key infrastructure project for Ireland, would provide a 19km link from Dublin city centre, via Dublin airport, north to Fingal.
EIB is also looking into two other public-private partnership projects in Ireland, the N17-N18 Gort to Tuam motorway link and the N11-N7 motorway.
These projects are part of the €2bn ($3bn) Irish National Roads Authority second roads PPP programme involving the Western Rail Corridor linking Cork, Limerick and Galway.
The bank, owned by 27 EU member states, said it provided €1.02bn ($1.5bn) for six projects in Ireland in 2009.