Rules in Poland's legal system that permit the country's justice minister to freely appoint or dismiss second judges to higher criminal courts violate EU law, the European Court of Justice ruled on Tuesday.

The decision came on a long-standing dispute between the EU and Warsaw over Polish judicial reforms that critics say breach the rule of law, curb judicial independence, and undermine the primacy of EU law.

The EU court's legal opinion had been requested by the Regional Court of Warsaw in connection with seven pending criminal cases, using the option of preliminary ruling that allows all national courts in EU member states to ask for support in interpreting EU law.

Poland's current regime jeopardizes the principles of judicial independence and presumption of innocence, with the justice minister able to freely appoint additional judges to criminal courts and terminate their secondment without any official criteria on the decision or right to appeal against it, the EU court found.

It argued that this system does not provide "the guarantees and independence that all judges should normally enjoy in a State governed by the rule of law" because the appointments can be used as a means of political control over the content of judicial decisions.

The preliminary judgment does not directly oblige the Polish government to change the legislation, but it can become another important argument in the bloc's dispute with Warsaw.

In October, the EU Court imposed a daily fine of €1 million ($1.1 million) on the Polish government for not complying with its previous ruling demanding the suspension of the activities of the Supreme Court's Disciplinary Chamber.

The European Commission also put on hold the approval of Poland's post-COVID recovery plan and the disbursement of €36 billion in recovery funding because of the lack of guarantees on judicial independence.