When Slovenia first endorsed introduction of the tax it supported "a broad tax base, a low tax rate, and simplicity," but the current proposal involves a "very narrow" tax base, Bratušek told parliament on Monday.

Current projections show that Slovenia would get EUR 3m from such a tax, but the cost of tax collection would amount to EUR 2m.

Meanwhile, Slovenia already collects EUR 40m annually from the tax on financial services and EUR 20m in tax on bank assets, which is "significantly more than the changed financial transactions tax would bring."

The government has been the subject of criticism by left parties and the union over its reluctance to push ahead with the tax.

The group of countries that want to introduce the tax as part of "enhanced cooperation" features Germany, France, Italy, Spain, Belgium, Austria, Estonia, Portugal, Greece and Slovakia.