"He is experienced, he knows how the EU operates, he has been working in diplomacy for a long time. This is what we presently need," Šarec said about Lenarčič.

A seasoned diplomat, Lenarčič has also served as ambassador to the OSCE, as director of the OSCE's Office for Democratic Institutions and Human Rights, as secretary of Slovenia's permanent UN mission, and as diplomatic adviser to the highest state officials.

Šarec said he had been weighing different options carefully since the EU election and came to the conclusion that, given the composition of the government, Slovenia needed a neutral candidate.

He also noted that his Marjan Šarec List (LMŠ) and the fellow coalition Social Democrats (SD) had each secured two MEP seats as the most successful coalition parties in the recent EU election, which is why he would not have found it fair to have the candidate come from either of the two parties.

He said that many opportunities had been missed by Slovenia and that it is right to give a chance to somebody who knows the workings of the EU.

Šarec is confident that the fellow coalition parties will also recognise the national interest of Slovenia and the importance of unity.

While the coalition partners Modern Centre Party (SMC), the Alenka Bratušek Party (SAB) and the Pensioners' Party (DeSUS) have declined to comment, the SD is openly critical.

"The unilateral decision by the prime minister is an unpleasant message," the SD said in a press release. Party leader Dejan Židan said that Lenarčič did not enjoy the party's support. He said that the SD's reservations will be evident "in all votes".

"There was an agreement that talks would still be conducted this afternoon, but we were faced with this information, his decision," said the head of the party which did not try to hide the fact the it wanted its MEP Tanja Fajon to be nominated.

Šarec said today that he could hardly imagine Fajon being a member of the Commission after having denied support to new Commission President Ursula von der Leyen publicly.

The party believes that "democratic legitimacy" was key in nominating commissioner, anything else is unacceptable to the SD, the party said in a press release.

Criticising what they see as political horse-trading that led to the appointment of von der Leyen with the support of far-right votes from Hungary and Poland, the SD said it expected "Slovenia would have acted differently and pick a Slovenian commissioner candidate with democratic legitimacy as a key condition" alongside competences, experience and reputation.

Meanwhile, Franc Trček, an MP for the Left, the minority government's partner in the opposition, said that Lenarčič was not enough of a "political and stately name for the demanding times the EU faces".

Opposition parties are yet to respond, however, the response of MEP Romana Tomc (SDS/EPP) is an indication that they may not approve. She finds it unacceptable that this nomination was a unilateral decision by the prime minister.

She believes that by proposing Lenarčič Šarec set Slovenia's ambitions to the level of civil servants.

If appointed, Lenarčič would become only third Slovenia's commissioner.

Janez Potočnik held the title for the first eight years after the country entered the EU, serving as the commissioner for science and research between 2004 and 2010, and the environment between 2010 and 2014.

Slovenia's current commissioner is Violeta Bulc, who is in charge of transport.