Poland's prime minister on Friday accused the Supreme Court of "destabilising the legal order" after it ruled that judges chosen by new government-backed institutions were not authorised to issue verdicts. The Supreme Court decided on Thursday that the judges were not free from outside influence, further inflaming a long-running controversy over reforms by the ruling Law and Justice (PiS) party. The PiS has passed a slew of judicial reforms arguing that they tackle corruption in a system still stuck in the communist era, but critics including top European judicial bodies say they undermine the rule of law and threaten democracy. Prime Minister Mateusz Morawiecki said he would refer the decision, which applies to some 500 judges, to the Constitutional Court -- controlled by judges nominated following the PiS reforms. He told reporters that the "unacceptable" decision had cast doubt on tens of thousands of rulings already delivered by the contested judges. Government spokesman Piotr Muller added that the Supreme Court's ruling was "aimed at undermining the foundations of the state's political system" and created "tremendous chaos of unprecedented scale". But Supreme Court spokesman Judge Michal Laskowski said on Thursday that the verdict did not have retroactive force and would not apply to court cases that had already begun. Also on Thursday, another hugely controversial reform that proposes disciplining judges who question the government's reforms moved one step closer to becoming law -- the PiS-controlled parliament approving it. The bill -- which critics say will gag dissenting voices -- now needs only to be signed by the president, who has indicated he will give it his assent. The European Union has repeatedly shown concern over the judicial changes. In 2017, it launched unprecedented proceedings against Poland over "systemic threats" to the rule of law that could see its EU voting rights suspended. via-amj/jxb