This is "the only realistic and cost-effective financing solution," the Chamber of Commerce and Industry (GZS) said.

The proposal comes amidst ongoing debates about the second rail line between Koper and the inland hub of Divača, a project decades in the making.

The plan has recently suffered two setbacks.

In June, Slovenia failed to secure funding under an EU scheme called Connecting Europe Facility.

In September, an OECD study found that the government's plan for a public-private partnership for the project was infeasible and economically unviable.

The GZS said today that launching the project through DARS would save the government from having to take on extra public debt.

Instead, DARS could build the track with commercial loans and funding from the European Investment Bank, albeit with state guarantees.

The contractor would be selected in an international tender, according to their proposal.

The GZS proposal came just before parliament started debating the project yet again, quizzing Infrastructure Minister Peter Gašperšič about the plan.

Gašperšič said various public-private partnership models were being explored, as is potential interest from neighbouring countries.

But Gašperšič downplayed alarmist statements by several MPs that the port of Koper would be severely constrained in the absence of the rail upgrade.

He said the current transport capacities should suffice until 2020 or 2025, whereupon the excess cargo would have to be transported by road.

But this proposal was describe by the GZS as "dangerous".

If current container transshipment volumes rise from the current 760,000 units to two million units per year, this would require an additional 1,650 lorries on motorways every year, the organisation said.