"What we want to achieve is of course that the bank is viable and an asset to the rest of the economy. When it was given state aid back in the days, the government took upon themselves a number of commitments in order for the bank not to get back into problems. This is why it is important to live up to the commitments," the commissioner said.

"A lot of progress has been made, but it is important to have this private ownership with publicly owned blocking minority in place. This is why we are in regular contact with the Slovenian government."

Vestager thus responded to a journalist question on whether she will approve Slovenia's proposal to delay the partial sale of the bank, for how long and under what conditions.

Slovenia committed to selling 75% minus one share in NLB in exchange for the European Commission approving a EUR 1.55bn in state aid to the bank in 2013.

At least 50% was to be sold by the end of this year and the rest until the end of 2018, but the government halted the two-phase procedure in June over dissatisfaction with the sale price and concerns over potential liabilities to Croatian savers.

In the state aid approval of 2013, the sanction envisaged for the country's failure to meet its commitment is selling NLB's Balkan subsidiaries. In this case the government should appoint a trustee, one endorsed by the Commission, to independently implement the sale process.

Slovenia's proposal has been to appoint a third party trustee for the management of NLB along with setting a new deadline for privatisation. Slovenia is also willing to compensate for the EUR 1.55bn in state aid to NLB.

Asked whether Slovenia's proposal to appoint a third party trustee was credible, Vestager did not wish to comment, saying that "one of the many privileges is that I can talk directly with the government" on the matter.

A two- or three-year postponement of the sale is said to be unacceptable to Brussels, which reportedly wants a realistic and clear time frame for fulfilling the privatisation commitment.

The potentially record-breaking profit expected at NLB this year is seen by some as a sign that now is the right time to sell the bank.