BUDAPEST, Hungary — Hungary’s prime minister is proposing a constitutional amendment that would ban the mass settlement of migrants without parliament’s approval.

Prime Minister Viktor Orban said Tuesday that the amendment would reflect the will of 3.3 million voters who, in a weekend referendum, supported the government’s opposition to any future attempts by the European Union to relocate asylum seekers. The referendum, nonetheless, was invalidated by low turnout.

Orban said that “there are 3.3 million people in Hungary who decided that they won’t allow anyone else to decide on … the matter of settlement and migrants.”

Orban said the composition of a country’s population was part of its “constitutional identity,” which Brussels had no right to change.

It was uncertain whether opposition lawmakers would help pass the amendment, which needs a two-thirds majority.