Addressing the press during a session of the SLS's main committee, Radovan Zerjav said that the party was insisting that the border issue needs to be solved before Croatia enters the EU.
This means that as opposed to only concluding an arbitration framework agreement, the arbitration or bilateral agreement needs to be wrapped up before Croatia concludes EU accession, he elaborated.
The party, which has been the most outspoken defender of Slovenia territorial claims, will moreover insist that the arbitration agreement cannot override the February parliamentary resolution dealing with the protection of Slovenian national interests.
Also, Croatia needs to "immediately start removing" material elements that prejudge the course of the border.
"And finally, given that things are going in the wrong direction and that the danger of Slovenia losing territorial contact to international waters is too great, we will definitely continue with activities for a subsequent referendum."
The SLS will start collecting signatures of support in principle for a referendum in Ljubljana on Saturday to establish whether is would be possible to collect the needed 40,000 signatures in case parliament ratifies the arbitration agreement.
As things stand now, "40,000 signatures should not be a problem", Zerjav said.