The law passed last month by Hungary's parliament bans the depiction of homosexuality or gender reassignment to minors in school education programs and media content.
Its passage set off a heated confrontation between Orban's right-wing government and the 27-member EU, which argued it discriminates against LGBT people and contravenes the bloc's fundamental values.
The referendum, Orban said, will feature five questions. They will cover such issues as whether children should be introduced to topics of sexual orientation in schools, and whether gender reassignment should be promoted or depicted to children.
It will also ask whether gender reassignment procedures should be made available to minors, he said, and urged Hungarians to vote “no” to each of the questions.
The announcement of the referendum comes as Orban, a frequent critic of the EU, faces intense pressure on several fronts ahead of elections next spring that are forecast to be the closest since he came to power in 2010.
His government is currently under fire over findings by an international investigation published last weekend that it used powerful malware to spy on critical journalists, politicians and business figures through their smartphones.
Opposition lawmakers have demanded an inquiry into the alleged spying by the parliament's national security committee, but delegates from Orban's Fidesz party indicated they will prevent the committee from convening, calling the reports “unfounded.”
Other high-ranking officials have refused to confirm or deny that the government used the spyware against Hungarian citizens.
Minutes after the announcement of the referendum, several opposition parties called for a boycott of the vote.
Peter Jakab, president of the right-wing party Jobbik, called the referendum plan a “clear diversion” from the spying allegations. The president of the centrist Momentum party, Andras Fekete-Gyor, said it was “a mockery of democracy and nothing more than gratuitous hate-mongering.”
On Tuesday, the EU's executive commission issued a report on EU members' adherence to the rule of law, where it outlined the erosion of democratic standards in Hungary, including inadequate anti-corruption measures and a deterioration of media pluralism.
The Commission has also opted to withhold payment of billions of euros (dollars) in EU economic recovery funds to Hungary until it implements judicial reform and strengthens anti-corruption frameworks, according to European justice commissioner Didier Reynders.
Orban cast the moves as an attempt by the EU to force Hungary to amend its controversial law on the depiction of homosexuality, though the rule of law report made no mention of that legislation.
FILE - In this file photo dated Thursday, July 8, 2021, Hungarian Prime Minister Viktor Orban during a press conference in Belgrade, Serbia. Prime Minster Orban said Wednesday July 21, 2021, a referendum was necessary in defense of child protection measures that many have criticized as an attack on LGBT rights, and to counter strong opposition by the European Union, which he said had “abused its power.” (AP Photo/Darko Vojinovic, FILE)
Credit: Darko Vojinovic
Credit: Darko Vojinovic