The article quotes the head of the Slovenian parliament's foreign affairs committee, Jozef Horvat, as saying, "Only after (the dispute) is solved in accordance with international law, will we be able to start the ratification procedure for Croatia's accession to the European Union."
EUobserver says Ljubljanska Banka owes EUR 172 million to 130,000 Croatian savers.
The portal says that "Horvat's statement will come as no surprise to Brussels" and cites unnamed diplomats as criticising Ljubljana for bringing bilateral issues into the enlargement process.
"Nobody in the EU likes it when EU matters are linked with bilateral problems ... If everybody did it, it would overshadow enlargement as a whole. Everyone could take something out of the bag against their neighbours and it would pollute the atmosphere," an unnamed EU source told the portal.
EUobserver also says this is not the first time that Slovenia is blocking Croatia's EU path. "In 2008, Slovenia threatened to stop Croatian accession talks over a maritime border dispute."