Talking about Croatia's problems with neighbours Slovenia and Italy, European Commission envoy Vincent Degert said many issues, like border disputes, were purely bilateral and had no impact on EU talks.
"But another case is obligations from the Stabilisation and Association Agreement (SAA). They will have direct influence on negotiations. We may decide not to open a chapter (of discussions) if certain obligations are not met," Degert told Reuters..
He said a typical contentious issue was that of Belgian bank KBC, which has complained to the European Commission about Zagreb's refusal to give it access to the Croatian market.
KBC has a stake in Slovenia's Nova Ljubljanska Banka (NLB), the successor to Ljubljanska Banka, which is at the heart of a row over debt to Croatian depositors dating from before Yugoslavia's 1991 break-up.
Croatia's central bank demands the debt issue to be resolved before NLB or KBC can come to Croatia.
Degert listed environment, competition policy, justice and home affairs, agriculture and budget as the toughest issues, or chapters, in Croatia's EU membership talks, Reuters said.
Later today, representatives of Croatia and the European Union should meet in Luxembourg later today to discuss Zagreb's progress in preparations for EU membership, including the implementation of regulation from the Stabilisation and Association Agreement.