Peterle, a member of the European Parliament for the conservative New Slovenia (NSi), a former prime minister and a former foreign minister, would have been "an excellent candidate".

He has "the necessary qualifications for the position" and enjoys "broad recognition across member states and institutions," Daul said in a written statement.

The statement comes a day after Prime Minister Alenka Bratušek said Peterle's candidacy was "not serious" as he formally lodged his bid just two days before the deadline for applications expired.

Additionally, she suggested the government was reluctant to support a person who signs petitions and resolutions by political groups which claim the situation in Slovenia is different than it actually is.

The statement referred to a November resolution by the EPP expressing concern about the economic and political situation in Slovenia, which also expressed concern about the conviction of opposition leader Janez Janša in the Patria corruption trial.

Daul labelled Bratušek's statements as "unfortunate". "I cannot accept the depreciating statements of Prime Minister Bratušek against a person of such stature, who expresses freely his political opinions," he said.

Bratušek cited another reason why she thought Peterle inappropriate candidate for CoE secretary general in a posting on her Fecebook profile today, noting that during Peterle's term as PM (1990-1992) 25,000 people were erased from the country's permanent resident registry in what was "the gravest human rights violation in independent Slovenia".

Peterle wrote on his Facebook profile yesterday that Bratušek's view was about political revanchism and a discreditation because he does not share the views of the government.

Ljudmila Novak, the leader of Peterle's NSi, said today she was "negatively surprised" about the government's stance. Considering his past achievements, the government should have "seized upon the opportunity."

Underscoring Peterle's view, the opposition Democratic Party (SDS) likened Bratušek's position to the then President Danilo Türk's failure in 2008 to endorse Dimitrij Rupel, a long-serving foreign minister, as ambassador to Austria.

"Both [Rupel and Peterle] were members of the DEMOS government, which implemented and defended Slovenia's independence, and attained the country's international recognition, but are inappropriate for international posts today because 'they are signing petitions or resolutions by political groupings'", SDS said in a press release.

The party condemned the reasons cited for non-support as a "language of discreditation and liquidation, a language of autocrats rather than democrats... This is the language of people who... communicated directly and cooperated with UDBA [secret police] and the language of their political successors."

The SDS goes on to say that Slovenia will be "closer to European normality when it will not propose for the post of UN secretary general people who have labelled a genocide a second rate topic", a reference to Türk's comments in 2009 related to the Huda jama post-WWII mass grave.