Initially, the ministry said a shortlist would be drafted by July and the best model picked in autumn.
The postponement comes after the project has not been approved for the EU's CEF funding mechanism for infrastructure projects.
Slovenia has hired the OECD to help with the PPP models for the construction of the track currently valued at about EUR 1.4bn.
The failure to get the funds has put Infrastructure Minister Peter Gašperšič in a tight spot; among other things, coalition partner Social Democrats (SD) demanded today a revision of the project application.
On the other hand, coalition Pensioner' Party (DeSUS) head Karl Erjavec seems to be more forgiving, saying that as long as the project comes through in autumn, there is no reason for concern.