The measure could take effect in a week at the earliest and will be used if necessary.

The amendments to the defence act received cross-partisan support, with only the opposition United Left (ZL) voting against after a lengthy debate that started on Tuesday evening.

The amendments proposed by the government include a new article stipulating that the National Assembly may authorise the Slovenian Armed Forces in exceptional circumstances to protect the border.

Soldiers would be allowed to warn, direct and temporarily restrict the movement of persons, as well as engage in crowd control, a measure put in place until necessary but no longer than three months, with optional extension.

The soldiers would have roughly the same powers as police officers based on a plan jointly prepared by the police and the General Staff.

The deployment required a two-thirds majority of the MPs, and it received more than that, with 66 of the total of 90 MPs voting in favour.

All deputy groups except the ZL, which wanted an intervention law to be passed, agreed with the proposal, arguing that help to the police was necessary to retain control of the situation on the borders.

Prime Minister Miro Cerar told the MPs at the session that the government was stepping up measures to secure adequate control of the inflow of migrants. The military has been already helping the police logistically, he added.

The additional powers granted to the army will be activated if the influx of migrants gets unmanageable for the units which are currently on the ground, Cerar said, while Defence Minister Andreja Katič added that the army would merely help the police and not take over police tasks.

The opposition Democrats (SDS) wanted even stricter measures to be taken, including the closure of the entire border with Croatia and equipping of police officers and soldiers with protective equipment.

The SDS and the fellow right-leaning opposition New Slovenia (NSi) agreed that fence should be erected on the border. Fence is necessary in order to provide security both for Slovenian citizens and refugees, NSi deputy Jernej Vrtovec said.

ZL deputy group head Luka Mesec meanwhile said that an intervention law would be better than changing a systemic law, while also pointing to the responsibility of the West for the situation in the countries from where the refugees are coming.

A group of around 30 people had meanwhile gathered in front of the parliament building during the extraordinary session to protest against changing of the defence act.

The changes are expected to enter into force in a week as the deadline for motions for a referendum will have passed by then.

Foreign Minister Karl Erjavec, the head of the opposition Pensioners' Party (DeSUS), said that the delayed entry into force was not a problem, adding though that the new possibility would probably be needed, because the "teams are tired".

Erjavec announced that he would have intensive talks in the coming days with the European Commission and some of his counterparts, primarily from the countries on the Balkan refugee route.

European Commissioner for Migration, Home Affairs and Citizenship Dimitris Avramopoulos will visit Slovenia on Thursday to talks about EU financial aid, material and technical aid to Slovenia in border control, he announced.