Head of DeSUS's deputy group Franc Jurša said that a formal proposal would be drawn up by Monday and that coalition negotiations on the matter would continue in the coming days.

This was confirmed by head of the deputy group of the senior coalition Positive Slovenia (PS) Jani Möderndorfer, who said the coalition would try to reach agreement on the matter on Monday.

"The maths is very simple. If you take something away from somewhere, you have to put the same amount back somewhere else," he said, confident the coalition would reach an agreement and pass the bill together.

Prime Minister Alenka Bratušek, who is attending the EU summit in Brussels, said she has not yet examined the proposal closely, but added that "reducing the base to 60% for next year practically means a complete loss of budget revenues from this source."

Bratušek reiterated she still believes that the coalition partner will act responsibly and constructively and that the National Assembly will confirm the tax and the 2014 budget.

After DeSUS proposed on Wednesday a more gradual introduction of the real estate tax, coalition partners said it should also say how to make up for the loss in revenue, which some estimates put at as much as EUR 40-70m.

SocDem leader Igor Lukšič said that the amendment proposed by DeSUS, which would not have the tax fully implemented until 2016, would have to be agreed among all coalition partners.

DeSUS proposes the tax base would be reduced to 60% of the property's generalised value in 2014 and 80% in 2015, while the current proposal envisages reducing the base to 85% only in the first year.

Proceeds from the real estate tax has already been factored in in the budget proposals for 2014 and 2015, so the amount of budget receipts would have to remain the same, which DeSUS's proposal "does not make possible, as it is only increasing the deficit", Lukšič said.

Citizens List (DL) leader Gregor Virant called DeSUS's proposal inconsistent in that it lacks revenue side measures as it would open a EUR 30m gap, while he also believes the phased in taxation should also apply to businesses.

If DeSUS deals with these two discrepancies, the DL is willing to back a lower real estate tax, Virant said, but was quick to add that his party was against a crisis tax, which DeSUS has been advocating in place of real estate tax.

Last night DeSUS leader Karl Erjavec assured reporters that gradual introduction would apply to all categories, but Jurša said today that the final content of the proposal was still open.

Virant also said that the coalition should pass the real estate tax bill together or not pass it at all, and that his party would probably not back it unless it has support of all coalition parties.

The opposition Democratic Party (SDS) meanwhile filed a request this morning for the National Assembly to reconsider the decision by the college of deputy group leaders to fast track the bill.

The vote is expected to be taken at an emergency plenary which has been called by Parliamentary Speaker Janko Veber for Friday.

The session will take place before the National Assembly resumes its plenary for October at 10 AM, with Veber allocating 20 minutes for the debate on the type of procedure the bill should undergo.