Hungarian Prime Minister Viktor Orban vowed Saturday to defend Poland against what he called an "inquisition" from Brussels, as Warsaw faces EU sanctions over controversial judicial reforms.

"In the interest of Europe and in the spirit of the old Hungarian-Polish friendship, the inquisition campaign against Poland can never lead to success," Orban said during a visit in Romania.

"Hungary will use all possible legal means in the European Union to show solidarity with the Poles."

Orban made the remarks during an annual speech at a summer university in the town of Baile Tusnad in eastern Transylvania, home to an ethnic Hungarian minority.

Polish senior officials were among those attending the conservative gathering.

Poland's senate approved a contentious reform of the Supreme Court early Saturday, which will see all serving judges replaced with candidates chosen by the justice minister. It is the latest in a slew of controversial legal changes that the ruling conservative Law and Justice (PiS) party says are necessary to make the judicial system more effective and fight against corruption.

But the EU has warned that the measures "considerably increase the systemic threat to the rule of law".

The European Commission threatened this week to move towards halting Poland's voting rights in the 28-nation bloc further down the line -- a so-called "nuclear option" never triggered thus far -- if Warsaw did not suspend its reforms.

Poland would, however, likely escape any such move thanks to close ally Hungary promising to block all attempts aimed at punishing Warsaw.

Together with Slovakia and the Czech Republic, the two countries form the Visegrad group, which has become a niggling thorn in Brussels' side.

The members regularly clash with the EU over their increasingly anti-globalist and anti-immigration stances.

Hailing Poland as "an example of sovereign national", Orban said Hungary stood "side by side with patriots".

He once again accused the "Brussels bureaucratic elite" of being bankrolled by Hungarian-born billionaire George Soros and various NGOs who, according to Orban, want to flood Europe with immigrants and destroy national sovereignty. And create a "new, mixed, Muslimized Europe".

He proceeded to raise the question of demographics and the clash of civilizations. "Will Europe be inhabited by Europeans? Will Hungary be inhabited by Hungarians, Germany by Germans, France by the French, Italy by Italians? Who will live in Europe?" he asked. "It is obvious that the culture of the immigrants is strongly opposed to the Europeans, to let them live next to each other leads to chaos," the Prime Minister said.