The parliament will have seven days to check the authenticity of the signatures. At the end of this period Speaker Gregor Virant will set a date for when the group will start collecting 40,000 signatures needed to call the vote.

Vili Kovačič of the initiative told the press before filing the signatures that these were collected by between 20 and 30 activists across the country.

He is confident that the NGO coalition will be able to collect the 40,000 signatures. Considering the summer recess, the speaker is expected to set the date for signature collection campaign for September.

Kovačič hopes the potential referendum will be carried out alongside presidential election scheduled for 11 November.

The referendum would ask the voters whether they are for the implementation of a recently passed act approving a EUR 110m state loan guarantee for a EUR 440m loan from the European Investment Bank (EIB) for the TEŠ power plant.

Even if the voters endorse the new generator, Kovačič believes there are additional reasons to stop the construction, including technical risks.

He said that boilers provided by Alstom, the main contractor on the project, are causing great problems for several German power plants.

Among those endorsing the referendum efforts are several renowned Slovenians, including philosophers Spomenka Hribar and Tine Hribar, journalist Bernard Nežmah, as well as director Dušan Jovanović and actress Milena Zupančič.