This will be Cerar's first meeting with Milanović and Austrian Chancellor Werner Faymann as part of trilateral cooperation launched in Austria's Graz in August 2013 after Croatia's accession to the EU, and resumed in Slovenia's Brdo pri Kranju in June this year.

Held twice a year, the trilateral summits are designed for the three nations to form ideas for a joint appearance in the EU and to boost bilateral relations, above all business links. The previous two meetings called for a joint fight against unemployment, efforts for economic growth and democratic Europe.

According to Cerar's office, the meeting in Opatija will discuss topics the trio "will support jointly at the December session of the European Council", including the EUR 3bn investment plan proposed by the European Commission President Jean-Claude Juncker. They will also discuss the Western Balkans.

As further topics Croatian media reports have also mentioned the Ukraine crisis and the impact of the EU sanctions against Russia and the counter-sanctions in its wake, after the Brdo meeting discussed energy issues, including the South Stream gas pipeline, which Russia has decided to abandon.

In what will be his first official trip to Croatia, PM Cerar will also meet his counterpart Milanović, with Croatian media suggesting they could broach the issue of Yugoslav-era savings deposits after Cerar told a recent interview that Slovenia could not be responsible for all debts of its defunct LB bank.

In an interview with the Zagreb-based daily Večernji list, Cerar said that the debts Croatian companies owe to LB bank were much higher than the bank's debt to its clients holding foreign currency deposits. He also raised the possibility of "legal means" unless a deal with Croatia was reached.