The court found the decision not to allow the referendum, which the National Assembly took on 4 November, is not in breach of the Constitution as a student radio station opposing the changed law claims.

In a unanimous decision, constitutional judges agreed that the legislative changes dealt with urgent security measures, which is why a referendum on them would be inadmissible.

This is the first ban of a referendum enabled by the 2013 constitutional changes governing referendums, which ban the popular vote on laws implementing emergency measures for defending the country or dealing with the consequences of natural disasters.

The judges upheld the National Assembly's assessment that the expansion of army powers might soon become crucial for national security.

The proponent of the referendum, editor-in-chief of Radio Študent Martina Dervarič, has failed to provide solid arguments that would undermine this assessment, the judges said.

Dervarič argued there was no need to expand the army powers, as the refugee crisis was primarily a humanitarian crisis.

Today, Radio Študent said it had expected the top court to rule the way it did, but that it was now waiting weather a petition for a review of the law would be brought by the Human Rights Ombudsman.

"We took on the matter due to a lack of any public debate whatsoever. We have initiated at least some discussion, but we expected such a decision from the Constitutional Court," Matej Janković of the radio said.

Since only the ombudsman or an army employee is eligible to challenge the law itself, the radio had asked the ombudsman to do so.

The ombudsman has given the government 20 days to explicate on the many contentious points in the legislation, whereupon the ombudsman will decide whether to challenge the law or not.

Passed by parliament in a two-thirds majority in late October, the changes to the defence act would enable giving the army limited police powers.

But a group of citizens led by Radio Študent launched the referendum procedure, which suspended the implementation of the new legislation.

The collection of signatures in support of the referendum was stopped by parliament, which banned the vote on 4 November.

In response, the referendum proponents requested a constitutional review of the ban in mid-November.

Now that the top court banned the referendum, the changes to the defence act are to step into force on Friday.

The changes will not automatically expand army powers though. If this proves necessary, the government will propose this to the National Assembly, where the request will need to be backed by a two-thirds majority.

The powers of soldiers will be expanded only for the period in which this is deemed urgently needed but not for longer than three months with the possibility of extension.