Orban, who earlier referred to illegal immigrants as "poison," said Friday on state radio that there may soon be a need to tighten borders further, if, for instance, Turkey refuses to help EU control the surge of migrants into Western Europe, as it does now in exchange for aid and visa-free travel for Turks. Turkish President Tayyip Erdogan has repeatedly said that European leaders are not living up to their part of the deal.
"Then if it does not work with nice words, we will have to stop them with force, and we will do so," Orban said.
The Prime Minister did not specify when construction will begin but noted that a new wall, to be built alongside the existing one, will be more fortified and able to stop anyone appearing at Hungary's frontier.
"Technical planning is under way to erect a more massive defense system next to the existing line of defense which was built quickly," he said.
Orban also announced that Hungary would increase its police force, deploying 3,000 new officers to the southern border.
He called for Europe's authorities to cooperate on ensuring the region's security, saying that joint efforts are required to defend borders between Serbia and Macedonia, and Macedonia and Greece.
Later on Friday, Orban and counterparts from Central European EU member states will meet in Warsaw with German Chancellor Angela Merkel. According to Orban, the politicians intend to change a policy by the EU, letting in migrants and distributing them among member states based on quotas.
"The question is whether Angela Merkel will be willing to change this flawed Brussels decision together with us. Whether she is willing to fight with us for this, or not," he said.
Hungary will hold a government-sponsored referendum October 2 on whether to accept any future EU quota system for resettling migrants.