Poland and Hungary have filed a complaint with the EU’s supreme court over a mechanism that ties respect for the rule of law with EU funding.
The rule of law mechanism was included in the budget approved last year by the EU, covering the 2021-27 period.
The two countries have been at odds with the EU for years over accusations their governments have been eroding judicial and media independence.
The bloc therefore included the rule of law mechanism in the budget - which includes a massive coronavirus stimulus fund - as a means of getting the two nations to adhere to EU values.
The right-wing governments of the countries have now officially lodged complaints with the European Court of Justice, with the Polish government spokesman, Piotr Müller claiming the mechanism “violates the law of the European Union”.
The challenge means that implementation of the new funding rule could be delayed up to two years, giving more breathing space ahead of the next national elections to Hungarian Prime Minister Viktor Orban's party Fidesz and Polish Prime Minister Mateusz Morawiecki's Law and Justice party.
The next parliamentary elections are scheduled in Hungary in 2022 and in Poland in 2023.
Poland and Hungary initially tried to block the budget from being passed but agreed to it on the condition the rule of law mechanism would be reviewed by the court.
Hungarian Justice Minister Judit Varga wrote on Facebook on Thursday that the mechanism “seriously infringes legal certainty”.
“The left went too far when it launched an attack on Hungary in the middle of the pandemic," she said.
“We repelled this attack and managed to defend Hungarian interests concerning the EU budget. However, what is unlawful cannot be left without a word."
Members of the European Parliament urged the European Commission on Thursday to activate the rule of law mechanism without delay.
They stressed “the continuous deterioration of the situation in some countries, including Hungary and Poland,” according to a statement released by the parliament.
The statement said that the budget commissioner, Johannes Hahn, told them that before the mechanism is used guidelines need to be completed, and that it should also take into account the European court ruling, which is expected in May.