The motion, presented by MP Andrej Vizjak of the Democrats (SDS), revolves around the claim that Omerzel lied about the business deals of his company Lastinski with the state-owned motorway company DARS in what is an apparent conflict of interest.

Omerzel's company signed a contract with DARS in 2008 for maintenance of weather stations. Before Omerzel took over as minister in early 2013, he told parliament that Lastinski would sign no new contracts with DARS.

However, according to Vizjak, in October last year DARS opened bidding for maintenance and Lastinski sent an offer in November, whereupon negotiations started.

"These negotiations lasted 20 minutes and a whopping 0.6% price reduction was agreed," Vizjak said. "Is this not clearly a conflict of interest? I think it is."

The contract was ultimately not signed, but Vizjak said this was due to disclosures by the media and the ensuing pressure.

Vizjak attributes the eventual rallying of troops behind Omerzel to the broader crisis in the ruling coalition.

"The minister's fate was hanging by a thread, but the thread thickened into a rope when other ministers ran into problems," he said.

The opposition also claims Omerzel violated the law on integrity and the prevention of corruption by not reporting his business deals to the Commission for the Prevention of Corruption, and for failing to prevent the price of unit 6 at the Šoštanj coal power station from surging.

Another reproach is that his ministry knew about massive fraud in the awarding of driving licences and safety certificates for two years but failed to take action.

Omerzel rejected all accusations in the motion, labelling them "devoid of content" and "bureaucratic".

He contended that the law prevented his company from doing business with the ministry he heads, not with DARS. "My company has never dealt with the Infrastructure and Spatial Planning Ministry."

As for the deals with DARS, Omerzel said it was DARS that had sought to extend the contract. "They decided who to licence for that." Now, however, the contract has been rescinded.

Prime Minister Alenka Bratušek also stepped up to to defend the minister. "He enjoys my support," she said in an address to the MPs.

According to her, many mistakes made in the past have surfaced during Omerzel's tenure. "His fault is that he did not sweep them under the rug as some before him."

Turning to the Lastinski-DARS contract, Bratušek said the deal was signed in 2008, when the SDS-led government was in power.

"If anything is wrong with this transaction I would expect you would have taken action. Don't blame it on the Alenka Bratušek government," she said.

The prime minister also touched on the allegation that Omerzel violated the ethics law, saying she was "very glad...we will all have the same standards from now on."

"Until recently [the outgoing head of the Corruption Prevention Commission Goran] Klemenčič was enemy of the state No. 1 according to what your party has been saying."

Minister Omerzel's position looked precarious until recently, but in the last week or so all coalition partners swayed to support him.

Following the presentation of the motion and Omerzel and Bratušek's responses, MPs will be presenting their views on Omerzel's actions throughout the day.

A vote on his dismissal is however scheduled for tomorrow.