"If we are forced to build a fence between Hungary and Croatia, we will do it," Orban said at a European Council press conference.
The prime minister added that it would be easier to "physically enforce" the border with Croatia than it was to build a fence on border with Serbia.
Last week, Hungary completed the construction of a 108-mile fence on the country’s southern border with Serbia to deter migrants from illegally crossing the country's border, triggering criticism from other members of the European Union.
Budapest estimates that over 156,000 migrants have illegally entered the country since the beginning of 2015.
The European Union is trying to tackle a massive crisis with hundreds of thousands of undocumented migrants attempting to cross into the bloc fleeing violence and poverty in their home countries in the Middle East and North Africa.