"We listened to Croatia's case today. I can say that there were no surprises. Their argument went as we expected," said Drenik. She did not reveal any details, as the hearing is held in confidence.

Croatia will continue to present their case tomorrow; following a day off on Wednesday, it will be Slovenia's turn to argue on Thursday and Friday. The same schedule will probably be repeated next week.

Present today was Croatia's Foreign Minister Vesna Pusić, while Slovenia's Foreign Minister Karl Erjavec will attend the hearing on Friday, when Slovenia is to talk about the border in Piran Bay, according to Drenik.

"We are happy that the hearing is conducted in front of a very professional and respectable arbitration tribunal, in front of arbitration judges into whose independence and impartiality we have total faith," Drenik said of the five-member tribunal.

A legally binding decision is expected within a year.