MEPs have urged the European Union to tackle alleged attacks on the rule of law in Poland "as a matter of urgency".
They say the bloc's core values are under threat from actions by the ruling conservative Law and Justice Party (PiS).
Brussels has frequently criticised reforms in Poland which it says undermines judges' independence from political control.
But, despite launching legal action against Poland on several occasions, the European Council has yet to take any formal action in suspending voting rights.
A statement from the European Parliament on Monday said most MEPs shared concerns over a "systematic and continuing attack against judicial independence".
Politicians have called on the European Council and Commission to take "decisive action" because Poland "poses a threat to the very structure of the EU".
Spanish MEP Juan Fernando Lopez Aguilar presented a draft interim report on the independence of the judiciary in Poland during a European Parliament debate on Monday.
Lopez Aguilar called on Poland to "defend democracy" and accused the government of "deliberately bringing the entire judiciary under its control".
“Judicial reforms in Poland constitute a serious, lasting, and systemic violation of the rule of law,” Lopez Aguilar told his fellow lawmakers.
"The EU Council must respond."
Socialist MEP Sylwia Spurek added on Twitter that Poland was detaching itself from the EU's key values.
The calls for action were also echoed by the President of the European Judges' Association, José Igreja Matos.
But some politicians from the EPP - the largest group in the European Parliament - have discussed that further input is needed from Polish authorities before any action is taken.
Polish MEP Patryk Jaki has further protested against the “extremely unprofessional” EU report, claiming that it contains “substantive errors”.
The European Union has previously voiced concerns over the threats to the independence of Poland's judiciary.
President Jaroslaw Kaczynski has been accused of weakening the rule of law to give the Law and Justice party power over the courts.
In December, lawmakers approved a controversial law that would allow sanctions against judges who opposed reforms.
The so-called 'muzzle-law' led to protests in Warsaw, attended by hundreds of judges from across Europe.
The EU has also voiced concerns over Poland's recent attempt to change the electoral code and hold presidential elections during the COVID-19 pandemic.
MEPs had warned that an election would undermine the Polish constitution if voters were unable to participate.
The elections were postponed with just four days to go after opposition from the country's Senate.
The European Parliament's Civil Liberties Committee will vote on the latest report into the rule of law in Poland in July, with plenary votes scheduled for later in September.
If the European Council determines that the rule of law has been seriously breached, the member state could be handed sanctions, including a suspension of voting rights.
Michal Šimečka, Vice-President of Renew Europe, told Euronews that the bloc must increase its efforts to sanction member states over breaches.
"If the EU wants to survive as a meaningful organisation delivering for all of its citizens, it will have to step up its response to the ongoing rule of law crisis".