Securing the functioning of the Schengen mechanism requires effective protection of the EU's outer borders, the prime ministers agreed.

"The current measures we are seeing internally in the EU, such as fences being built among members, have been caused by a lack of a joint action on the external border," said Cerar as he reiterated his plan for bolstering security on the external EU border.

He said the plan, which calls for speedy implementation of an accord with Turkey on limiting migration flow and assistance to Greece and Macedonia in securing their borders, was backed by Orban as part of today's joint session of the Slovenian and Hungarian cabinets.

Cerar reiterated that Greece must be provided assistance in the form of the coast guard and personnel of the EU's external borders agency Frontex quickly. A second line of defence to prevent uncontrolled migration must be set up at the Macedonian-Greek border.

The Slovenian prime minister warned that time was running out, reiterating his warning that tensions which could arise as the migration crisis intensifies could lead to conflict between countries on the migration route. "We don't have time until spring to find a solution."

Assessing that the migration crisis had ballooned in magnitude in recent months and had achieved a new degree of complexity, Orban urged "going back to the roots". "And at the roots is the Schengen agreement, which means upholding the system for which we signed up."

He argued that EU countries had a duty to respect the agreements that they signed and could not afford to allow exceptions. The EU is an bloc built on agreements, without respect for which it begins to unravel, he warned.

Stressing support for Cerar's plans for bolstering security on the outer borders, Orban said that "Schengen cannot be defended with words but with actions". He said that this included building a fence on the Macedonian and Bulgarian borders with Greece if need be.

Cerar used the joint cabinet session to thank Hungary for its support to Slovenia in managing the refugee flow, which includes a contingent of over 50 Hungarian police officers.

He also reiterated the importance of the razor wire fence Slovenia has erected on its border with Croatia in a bid to control migration flows, calling it "an effective message to anyone who would want to move migrants without agreement uncontrollably and without agreement with its neighbours".

"The technical barriers have protected Slovenian citizens, their houses, their fields, their vehicles, their property...and prevented the possibility of thousands flooding in uncontrollably and perhaps even posing a threat to locals in their distress."

He pledged that the fence was a temporary measure and would be removed once the EU finds a common solution.

The joint session of the government, which started with a three hour delay due to a technical fault on the aircraft that was due to carry the Hungarian delegation, also reviewed cooperation in the protection of the respective minorities.

Cerar labelled the Slovenian minority in Hungary and Hungarian minority in Slovenia as a vital bond between the countries. "The minorities are protected well by the respective countries, but there is room for improvement, especially in financing," he said.

As part of today's visit, Hungary opened a Cultural Institute in Ljubljana with the aim of fostering cultural exchange between the countries and promoting interest in Hungarian culture.