Citing the latest case that occurred on Saturday when a Croatian fishing boat entered the bay under police escort, the SLS said that this proved that Croatia was gradually taking control of a half of the bay in order to ensure the best possible position in the event of international arbitration over the sea border.
The party proposed that the Slovene government transfer the dispute over fishing in the Bay of Piran to the European Commission.
Three weeks before a parliamentary election in Slovenia, the Rop government is under growing pressure over incidents arising from different interpretations of the provisional delimitation of the Bay of Piran.
A few months ago the SLS decided to leave the coalition government and join the opposition. It scored poor results at May's elections for the European Parliament.
Leading Slovene newspaper Delo said in a comment on Saturday that an increasing number of Croatian fishing boats entering the bay under police escort proved that Croatia was preparing for arbitration and was changing "step by step" the situation regarding control of the bay. It said that at the moment Slovenia and Croatia became independent states Slovenia had the entire bay under the control of its police.