"The government has not yet debated that or made any decisions. I can say that he definitely has my personal support," Bratušek told reporters after the EU summit in Brussels.

Her statement comes after daily Delo reported Thursday, quoting unofficial information, that the Slovenian diplomatic network had been instructed to start laying the groundwork for Türk's candidacy.

It has long been speculated that after he failed to win re-election in 2012, Türk would seek a senior position at the UN, where he served as Slovenia's ambassador between 1992 and 2000 and then as assistant secretary general between 2000 and 2005.

The rumours have grown louder in recent weeks since his benefits as the former head of state - special status as well as an office and paid assistant - expire next week, a year after he left office.

Türk's office told the STA that he was "willing to run for UN secretary general in principle" when the time is right, adding that his candidacy would be "useful for Slovenia".

Candidates for secretary general are not proposed by individual countries, though their support matters. They are put forward by geographical groups and the Eastern European group has never had a secretary general before.

Ban's second term at the helm of the organisation ends in 2016.