"We are counting on signing a private investor towards the end of 2016, until which time the construction permit will have been secured and construction launched," he told Monday's edition of Primorske novice newspaper.

He said the schedule was in line with the demand that Slovenia must upgrade its rail network to standards required for designation as a pan-European transport corridor.

"If we start construction of the second track [between Koper and Divača] at the end of 2016, we'd finish by 2023," he said.

The Koper-Divača investment is currently valued at EUR 1.4bn, but questions have been raised about the price tag that to many seems excessive for what is a 27-kilometre track.

Gašperšič said an international audit of the investment value would be carried out in cooperation with the Organisation for Economic Cooperation and Development (OECD), with results expected early in 2016.

The Koper-Divača rail upgrade is inextricably linked to the Port of Koper, as the sole objective of the upgrade is to allow the transit of higher cargo volumes.

There have been plans in the past to join together port operator Luka Koper and rail operator Slovenske železnice, but more recently it was speculated that Luka Koper could be privatised to sweeten the deal for potential private partners in the rail upgrade.

While the majority state-owned Luka Koper has been designated as a strategic investment and Prime Minister Miro Cerar recently reiterated it would not be privatised, Gašperšič suggested the government was open to other solutions.

"If it turns out that a model involving a reduction of the state's equity stake in Luka Koper would be more efficient and profitable, we will launch a debate on that," he said.