The European Parliament launched a lawsuit against the bloc's executive on Friday for failing to apply a new law that allows the freezing of EU payments to countries which do not respect rule-of-law principles.
Poland and Hungary are both under formal EU investigation for not respecting the rule of law and stand to lose tens of billions of euros if the law is successfully applied to them.
The executive European Commission, which is the guardian of EU laws, has said it would only apply the law, called the conditionality regulation, once the EU's top court rules it is in line with EU treaties -- a ruling that might come next year.
The Commission's decision to delay application of the law is part of a deal made in December 2020 between EU governments and Poland and Hungary that a court ruling on the law would have to come first.
Poland and Hungary challenged the law in the Court of Justice of the European Union in March.
The parliament argues, however, that the Commission is obliged by the treaties to apply EU laws when they come into force, without waiting for a court ruling on their validity. The law linking EU money to respect for the rule of law has been in force since Jan. 1.
"The Parliament's legal service today submitted the lawsuit against the European Commission for its failure to apply the Conditionality Regulation to the Court of Justice," the parliament said in a statement.