The Slovenian government has proposed a law that will enable the army to help police guard the border as thousands of migrants entered into the Balkan country from Croatia.
The bill, proposed overnight, is expected to be passed by parliament later on October 20.
The move comes as Slovenia blocked entry to more than 1,000 migrants arriving from Croatia on October 19, saying a daily quota had been reached.
Croatia had asked its northern neighbor to accept 5,000 migrants daily but Slovenia insisted it would only take half that number.
It has led to a build-up of migrants in Croatia and Serbia.
Tens of thousands of migrants – mostly fleeing violence in Syria, Afghanistan, and Iraq – are travelling north through the Balkans, aiming to reach Western Europe.
The migrants switched to a route via Slovenia when Hungary closed its border with Croatia and Serbia.