The European Union will "start falling apart" if it fails to take concrete action to tackle the migrant crisis within the next few weeks, Slovenian Prime Minister Miro Cerar warned Sunday.

"If we do not deliver some immediate and concrete actions on the ground in the next few days and weeks I believe the EU and Europe as a whole will start falling apart," Cerar, whose tiny country of two million has been swamped by more than 60,000 migrants in a matter of days, said as he went into a refugee mini summit in Brussels.