The final vote was 39-23 in favour of the motion, which despite winning more votes for than against fell short of the required absolute majority in the 90-seat National Assembly.

The vote came after more than 10 hours of debate on the motion that accused the minister of political staffing and double standards in applying political ethics.

The main reproach against Virant by the opposition was the allegedly dubious purchase of heavily discounted tickets from flag carrier Adria Airways in 2008-2010.

It argued that he broke the very ethical rules in politics for which he has stood publicly, while also saying he was responsible for questionable staffing decisions.

In his defence, Virant rejected the motion as "bogus" and argued that it had been proposed by those who are the target of various police investigations as a means of payback.

While most of the coalition sided with him in rebutting the motion as unfounded, the PS decided to stay away from the vote, bar a handful of rogue MPs who contributed their votes to the yes camp.

The outcome ended days of speculation on what the PS would do and opens new questions about how its decision will impact on the coalition. The DL warned that a failure to back the minister would send the wrong message to the coalition partners.

The coalition has been facing tension all week over how to salvage the budget following the collapse of the real estate tax, after the proposal by Finance Minister Uroš Čufer to increase value added tax (VAT) was promptly turned down by DL.

The boycott was signalled already in the morning by Prime Minister Alenka Bratušek, who rubbished the motion as "the worst argumented interpellation to date" but stopped short of voicing support for the minister.

She said that "instead of wasting 10 hours here for a pointless debate about the life of Minister Virant", PS lawmakers would meet with her on ways to offset the lost revenues from the real estate tax.

But she also appeared to extend an olive branch to DL by saying that the VAT hike was off the table and calling a meeting of the coalition on the issue on Sunday. She then went on to announce that she would call a vote of confidence in her government in the near future.