Viktor Orbán and Benjamin Netanyahu shake hands at the end of a press conference in Budapest. Photograph: Attila Kisbenedek/AFP/Getty Images

Hungary will leave the international criminal court because it has become “political”, the country’s prime minister, Viktor Orbán, said as he welcomed his Israeli counterpart, Benjamin Netanhayu – the subject of an ICC arrest warrant – to Budapest for an official visit.

Standing beside Netanyahu at the start of the four-day visit, Orbàn said Hungary was convinced the “otherwise very important court” had “diminished into a political forum”.

Netanyahu hailed “a bold and principled” decision. “I thank you, Viktor … It’s important for all democracies,” the Israeli prime minister said. “It’s important to stand up to this corrupt organisation.” Netanyahu has been under an international arrest warrant since November over allegations of war crimes in Gaza.

He also said he believed Israel and Hungary, both of which are led by rightwing nationalist governments, were “fighting a similar battle for the future of our common civilisation, our Judeo-Christian civilisation”.

Orbán’s chief of staff, Gergely Gulyás, announced shortly after Netanyahu landed at Budapest airport that the government would “initiate the withdrawal procedure on Thursday in accordance with the constitutional and international legal framework”.

Leaving the court, to which all 27 EU members belong, would entail first passing a bill through parliament, dominated by Orbán’s Fidesz party, then formally notifying the UN secretary general’s office. Withdrawal would come into effect one year later.

Israel’s foreign minister, Gideon Saar, welcomed what he termed an “important decision”, adding that the “so-called international criminal court” had “lost its moral authority after trampling the fundamental principles of international law in its zest for harming Israel’s right to self-defence”.

The Dutch foreign minister, Caspar Veldkamp, however, told reporters on the sidelines of a Nato meeting in Brussels that as long as Hungary remained officially a member of the ICC, it should “fulfil all its obligations to the court”.

The ICC’s governing body voiced concern over Hungary’s decision, saying any departure “clouds our shared quest for justice and weakens our resolve to fight impunity”. It said the court was “at the centre of the global commitment to accountability” and the international community should “support it without reservation”.

Netanyahu was welcomed in Budapest in an official ceremony, standing alongside Orbán as a military band played and cavalry carrying swords and bayonets passed by. He is expected to tour Budapest’s Holocaust Museum and hold a number of political meetings before leaving on Sunday.

Orbán invited his Israeli counterpart to visit in November, the day after the ICC, which is based in the Hague and is the world’s only permanent global tribunal for war crimes and genocide, issued the warrant. The ICC’s move was described by Israel as politically motivated and fuelled by antisemitism.

Netanyahu’s government has repeatedly said the court has lost its legitimacy by issuing a warrant against a democratically elected leader exercising his country’s right to self-defence after the October 2023 attack by Hamas-led fighters on southern Israel.

Viktor Orbán and Benjamin Netanyahu on the red carpet during a welcoming ceremony at the Lion’s Courtyard in Budapest. Photograph: Bernadett Szabó/Reuters

Liz Evenson, the international justice director at Human Rights Watch, said Hungary’s withdrawal would “demonstrate how far Orbán’s government is willing to go to diminish protection of human rights globally and respect for the rule of law for people including in Hungary”.

The country’s ICC obligations “remain intact”, Evenson said. In principle, Hungary, a founding member of the ICC treaty, should be required to detain and extradite anyone subject to a warrant from the court.

Budapest, however, argues it never promulgated the law, so ICC measures cannot legally be carried out within Hungary. Many legal experts say that as a signatory and ratified state party, Hungary is nonetheless obliged to uphold the ICC’s Rome statute.

Orbán, in any case, has said he would not respect the court’s Israel ruling, which he has previously described as “brazen, cynical and completely unacceptable”.

The Hungarian prime minister has strongly supported Netanyahu for many years, embracing him as an ally who shares the same conservative, sovereignist and authoritarian views. Hungary has frequently blocked EU statements or sanctions against Israel.

The visit marks Netanyahu’s second trip abroad since ICC warrants were announced against him and his former defence chief Yoav Gallant, as well as for the Hamas leader Mohammed Deif. In February, he travelled to the US, which – like Israel, Russia and China – is not a member of the ICC.

For the Israeli prime minister, the visit is a chance to show – at a time of mounting criticism of his leadership and a lengthening list of domestic scandals – that despite widespread international opposition to Israel’s conduct of the war he remains a leader on the world stage. For Orbán, it is another act of attention-grabbing defiance.

ICC judges said when they issued the warrant that there were reasonable grounds to believe Netanyahu and Gallant were criminally responsible for acts including murder, persecution and starvation as a weapon of war.

EU members are divided over whether to enforce the warrants, with some, such as Spain, the Netherlands and Finland, saying they would enforce them and others, including Germany and Poland, suggesting they could find a way for Netanyahu to visit without being arrested. France has said Netanyahu should be immune from the warrant since Israel is not an ICC member.

The court, whose 124 members also include the UK, Canada, Australia, Brazil, Japan and many African, Latin American and Asia-Pacific countries, aims to pursue people responsible for grave crimes when countries cannot or will not do so themselves.

It has opened more than 30 cases for alleged war crimes, crimes against humanity, genocide and offences against the administration of justice, but is hampered by a lack of recognition and enforcement. Only Burundi and the Philippines have so far left the ICC.

Jon Henley Europe correspondent