The presidents of the six central European countries - Czech Republic, Hungary, Poland and Slovakia plus Austria and Slovenia - will discuss ways for upgrading transport integration in central Europe, Pahor's office said.

The summit will be the first at which the heads of state from Austria and Slovenia will join the four countries of the group for a meeting at the highest level.

Other infrastructure projects, including in energy and communication, are expected to be broached, with one of the likely topics being the fallout of Russia's announcement that it is halting the construction of the South Stream gas pipeline.

Meanwhile, Financial Times reported on Tuesday that the meeting would focus on cooperation in tapping the EUR 315bn investment fund being set up by the European Commission.

Pahor's office said that each president is expected to present one key project from their country which would bid for money from the fund. The six countries are also expected to examine the possibility of joint projects.

The six countries want to coordinate their actions in order to gain greater negotiating influence when the time comes to divide the money from the fund. Coordination among the group had proved successful already in negotiations on the 2014-2020 EU budget framework.

Key foreign policy issues, including the crisis in Ukraine, integration of the Western Balkans in the EU and NATO and the fight on Islamic State, are also expected to be raised at the summit.

Pahor's office said that participation of the meeting in Prague is "confirmation of Slovenia's central European character" and confirmation of the desire to work closely with the Visegrad group of countries.

Slovenia and the Visegrad Group are linked by one of the key corridors in the Trans-European Transport Network which connects the Baltic with the Adriatic. In Slovenia the corridor links the port city of Koper to Ljubljana and then on to Maribor.

The Koper port is seen as a key logistics gateway on the route, providing a way for goods from Central Europe to enter and leave. As part of efforts to expand its capacities, Slovenia has been mulling building a second rail track between Koper and the logistics hub of Divača.

While Slovenia is not a member of the Visegrad Group, which was established to promote cooperation among its four members following the fall of the Iron Curtain, it has participated in several meetings as a partner.

Goods trade with the four countries of the group amounts to EUR 4.5bn a year, while Slovenia exchanges another EUR 5bn in goods with Austria.

On the margins of the summit, Pahor is also scheduled to hold a bilateral meeting with Zeman, as part of which the pair will inaugurate a rootstock of the old vine from Maribor - considered to be the oldest vine in the world - at Prague Castle.