BRUSSELS (Reuters) - The European Union’s top court indicated on Wednesday that it agreed with the assessment of the EU’s executive that the independence of Polish courts could be at risk from changes made by the right-wing government.

The European Court of Justice (ECJ) found that the EU executive, the European Commission, had made a “particularly relevant” assessment in a document last December which said that “judicial reforms in Poland mean that the country’s judiciary is now under the political control of the ruling majority”.

The ECJ was ruling on a case brought by an Irish judge, who asked if a Pole being sought under a European arrest warrant should be extradited to Poland if changes to the judiciary put the independence of courts in doubt.

The ECJ said Ireland should refuse extradition if it concluded that the lack of independence of Polish courts would compromise the suspect’s right to a fair trial.

And it said that the “reasoned proposal” put forward by the Commission in December was particularly relevant for such an assessment.

“In the absence of judicial independence, serious questions are raised about the effective application of EU law, from the protection of investments to the mutual recognition of decisions in areas as diverse as child custody disputes or the execution of European Arrest Warrants,” the Commission said.

Since the nationalist PiS party won power in Poland in 2015, it has pushed through laws under which dozens of judges have been dismissed from the Constitutional Tribunal, the National Judiciary Council, which decides appointments, and the Supreme Court.

It has also moved powers concerning the appointment of new judges from judicial bodies to parliament, where PiS has majority.

As a result, the Commission is investigating Poland on suspicion of undermining the rule of law.

The ECJ said on Wednesday that, for Poland’s courts to be independent and impartial, they had to “exercise their functions wholly autonomously, shielded from external interventions or pressure”.

In a reference to the sacking of judges and appointment of new ones by Justice Minister Zbigniew Ziobro, a member of the PiS, and to measures shortening the term of Supreme Court judges, the ECJ said:

“Guarantees of independence and impartiality require rules, particularly as regards the composition of courts and the appointment, length of service and grounds for abstention, rejection and dismissal of their members.”

The PiS has also set up a Disciplinary Chamber for the judiciary, presided over by a single judge chosen by the justice minister.

“The disciplinary regime governing their (courts’) members must display the necessary guarantees in order to prevent any risk of that regime being used as a system of political control of the content of judicial decisions,” the ECJ said.