The letter to the European Commission, which is the first step in the procedure before Slovenia can turn to the Court of Justice of the EU, was presented to PM Miro Cerar by Foreign Minister Karl Erjavec on Wednesday.

Speaking after the meeting, Erjavec said that he had been given a green light for the contents of the letter to be presented to the government behind closed doors at the weekly session tomorrow.

Cerar said that apart from sending the letter to Brussels, the government would adopt a resolution saying that if the European Commission fails to initiate proceedings against Croatia, this should be done by the Slovenian government.

"This way the government, while being still fully empowered, will take a key decision that can then be executed by the government before or after the election, even though no longer fully empowered," Cerar told reporters.

It is vital that the government takes all the necessary decisions now in cooperation with the National Assembly, so Cerar plans to present the draft letter to the Foreign Policy Committee.

Cerar said that he could not reveal the details of the letter which was still being prepared, but he did assess that the draft was well set out and that the same assessment would be made by the committee.

He believes that cross-partisan unity is essential and should be preserved because the procedure will be lengthy and will also require the involvement of future governments. "Therefore, it's vital to lay out the groundwork so that any future government can carry out the procedures successfully."

Speaking separately, Erjavec said that the letter contained all the necessary elements to submit a lawsuit against Croatia at the EU court for its failure to implement the border arbitration decision.

Once it gets the go-ahead from the Foreign Policy Committee, the government will send the letter to the European Commission, which Cerar believes should be done as soon as possible.

"We have the substantiation and the grounds to argue that Croatia violates European law," Cerar said.

Erjavec and Cerar were joined at the meeting by the ministers who are members of the taskforce in charge of the implementation of the arbitration award, as well as by the team of lawyers who will represent Slovenia.

The information available so far indicates that Slovenia will send the letter to the Commission based on Article 259 of the Lisbon Treaty, thus launching the process to sue Croatia over its failure to implement the 2017 arbitration decision.

Once the case is presented to the European Commission, the latter has three months to take its position on the matter. If the Commission is opposed or fails to take a position, this does not prevent the country to bring the case to the EU court by itself.

Erjavec commented that it was hard to say what the Commission would do, "having so far failed to do what's essential when it comes to respecting the arbitration award by Croatia".

"If it doesn't back our letter, I expect it to state that as soon as possible so that legal proceedings can be launched at the EU court in Luxembourg as soon as possible," Erjavec said, adding that the issue was a legal rather than a political one.

The unofficial information this far does not indicate the Commission will take any legal steps against Croatia, so Slovenia will most likely pursue the lawsuit against Croatia on its own.