Polish Prime Minister Mateusz Morawiecki has accused European Union institutions of infringing on the rights of member states as he prepared to present the country's position in a row over the rule of law next week before the European Parliament.
Poland's nationalist government has been at odds with the European Commission in Brussels over judicial reforms, media freedoms and LGBT rights since taking power in 2015 but a recent court ruling that parts of EU law are incompatible with the Polish constitution has brought matters to a head.
"We are at a crucial moment, you could say at a crossroads in the EU's history," Morawiecki told the Polish parliament.
"Democracy is being tested - how far will European countries retreat before this usurpation by some EU institutions?"
The ruling by Poland's Constitutional Tribunal, an institution the government's critics say has become politicised as part of reforms they say undermine judicial independence, challenges a key tenet of European integration.
Poland says the EU has overstepped its mandate by attempting to prevent the government's judicial reforms and that the Constitutional Tribunal ruling asserts the primacy of the Polish constitution in a way that is no different from rulings handed down by courts in other European countries.
Asked about Morawiecki's comments on Thursday, Commission spokesman Christian Wigand said the EU executive had "the task of safeguarding the proper functioning of the Union's legal order... and will ensure that the rights of Europeans under the Treaties will continue to be protected..."
He said an in-depth analysis of the Polish court ruling was underway, adding that an initial assessment pointed to "very serious issues in relation to the primacy of EU law".
The court ruling could put at risk 23 billion euros ($A36 billion) in EU grants and 34 billion euros in cheap loans that Poland could otherwise count on as part of the EU's recovery fund after the COVID-19 pandemic.
It has also spurred talk of a "Polexit" although officials in Warsaw say they have no intention of following the United Kingdom out of the EU.
Polish government spokesman Piotr Muller said Morawiecki would attend the European Parliament session in Strasbourg next Tuesday to present Poland's position in the rule of law dispute.
Australian Associated Press