Hungary must pay a 200-million-euro ($216 million) fine for not implementing changes to its policy of handling migrants and asylum seekers at its border, the European Union's top court said on Thursday.

"The decision is outrageous and unacceptable," Prime Minister Viktor Orban said in a Facebook post.

Budapest's nationalist government, which has previously refused to carry out the 2020 court ruling, will also be required to pay a daily fine of one million euros ($1.08 million) until it fully implements the measures.

In its verdict, the European Court of Justice said Hungary had failed to take measures "to comply with the 2020 judgment as regards the right of applicants for international protection to remain in Hungary pending a final decision on their appeal against the rejection of their application and the removal of illegally staying third-country nationals".

Orban's government has argued that the 2020 ruling was moot as it had already closed so-called "transit-zones" while also hardening rules to bar future asylum applicants.

Under current legislation, people can only submit requests for asylum outside Hungary's borders, at its embassies in neighbouring Serbia or Ukraine. Those who try to cross the border are routinely pushed back.

Orban, who has often clashed with the EU's executive commission on issues ranging from the independence of the Hungarian judiciary to sending arms to Ukraine, vowed in 2021 to "maintain the existing regime (regarding asylum seekers) even if the European court ordered us to change it".

The European Commission filed a second application to the court in early 2022, saying Hungary had not taken all necessary measures to comply with the panel's 2020 judgment.

"That failure, which consists in deliberately avoiding the application of a common EU policy as a whole, constitutes an unprecedented and extremely serious infringement of EU law," Thursday's ECJ verdict read.