A hearing has been scheduled for March.

The tribunal has given Croatia until 15 January and Slovenia until 26 February to make further submissions "concerning the legal implications of the matters set out in Croatia's letters of 24 July 2015 and 31 July 2015."

In the letters in question Croatia said it considered the arbitration procedure "tainted" due to contacts between Slovenia's agent in the process and Slovenian member of the arbitration panel.

It also informed the judges of its intention to terminate the agreement that served as a basis for the establishment of the arbitration tribunal.

Slovenia in turn replied that it had "objected to Croatia's purported unilateral termination of the Arbitration Agreement" and took the view that the Tribunal has "the power and the duty to continue the proceeding," the tribunal said today.

The Slovenian Foreign Ministry confirmed for the STA it had received the tribunal's notification and said the government would make its submissions by the indicated date.

"Slovenia continues to support the arbitral tribunal and the arbitration procedure, confident that it will result in a legally binding judgement," the ministry said.

The arbitration tribunal was originally expected to reach a decision by the end of this year.

The procedure was thrown off track after Croatian media published recordings this summer of Slovenia's arbiter, Jernej Sekolec, conversing with Slovenia's agent at the court, Simona Drenik, in violation of the rules.

Sekolec and Drenik stepped down, Croatia immediately proclaimed the process dead and its arbiter resigned, but Slovenia insists that a unilateral withdrawal is not possible.

The president of the tribunal, Gilbert Guillaume, appointed two new judges in late September.