The resignations came after PM Miro Cerar said earlier today that the alleged contacts between the pair had been inappropriate and that he expected them to accept responsibility.

Sekolec's resignation was already confirmed by the Permanent Court of Arbitration in the Hague, which said the Slovenian government must now appoint a new member of the arbitration tribunal within 15 days.

If it fails to do so, a replacement is to be appointed by the president of the tribunal.

Once the five-strong line-up is complete again, the tribunal plans to resume the arbitration procedure without delay, the Hague court, which acts as a secretariat for the tribunal, said.

Sekolec, who has not been available for comments, was appointed Slovenia's member of the arbitration tribunal by parliament in September 2011. He was the only candidate to apply for the post.

The leaked recordings of tapped conversations raised a lot of dust in Slovenia and Croatia.

While in Slovenia reactions varied from surprise to disbelief and criticism of Croatia's illegal wiretapping of the conversations, everybody agreed that the tribunal should continue its work.

Both Cerar and President Borut Pahor, who was prime minister in 2009 when the border arbitration agreement with Croatia was signed, said that they wanted the tribunal to complete its work.

Similarly, Danilo Türk, who served as Slovenia's president in 2007-2012, when the arbitration tribunal was formed, said the issue did not affect the validity of the arbitration agreement.

Political parties were rather reserved and called for unity. Matej Tonin of the opposition New Slovenia (NSi) said that the same coordination also took place on the Croatian side and that any divisions in Slovenia now only benefited Croatia.

In Croatia, however, calls were heard that the country should withdraw from the arbitration agreement.

President Kolinda Grabar-Kitarović said during a visit to Israel that the incident questions the objectivity of the procedure, while Foreign Minister Vesna Pusić confirmed that the possibility of a withdrawal from the agreement was being discussed.

International law professor Silvo Devetak of the Maribor Faculty of Law however explained for the STA this was theoretically possible but highly unlikely and anything but simple.

Slovenia's Foreign Minister Karl Erjavec, who said yesterday he would cut short his holiday due to the incident, was unavailable for comment today.

Slovenian Ambassador to Croatia Vojko Volk believes the fallout from the scandal will affect the Slovenian-Croatian relations much more than anyone could imagine at the moment. The issue will also affect the region, according to him.

"Learning that the ruling will be unfavourable for Croatia, the country resorted to extreme measures, using products of intelligence services and secret recordings of their allies and the international court with the purpose of tainting the work of the court and the final ruling," Volk said.

Croatian honorary consul in Slovenia Božo Dimnik believes that the incident has been blown out of proportion. He believes talks between judges and agents were nothing out of the ordinary, that Croatia was doing the same thing and that this would not affect the outcome.

The incident also raised questions about Croatia's listening in on confidential talks between Slovenian officials, so the parliamentary Intelligence Services Oversight Commission held an extraordinary session dedicated to the topic.

Its head Branko Grims said the Slovenian intelligence services were investigating at least eight possible sources of the leaked wire taps.