Whole EU didn't break him: Orban made clear Hungary will not back down
EPs are debating whether his right-wing government's policies on issues like migrants pose a threat to the EU.
It comes just months after the European Commission took the step of launching similar proceedings against Poland, BBC reported.
However, this is the first time parliament has tried to use the power, known as Article 7.
Dutch MEP Judith Sargentini, who wrote a report into Hungary and Mr Orban's Fidesz party, launched the debate.
She said her report "comprehensively lists" attacks on the media, minorities, and the rule of law, that represent "a clear breach of the values of our union". Hungarian Prime Minister Viktor Orban arrived late to the proceedings before launching a blistering attack on the EU and Ms Sargentini's report.
He denounced it as an "abuse of power", and said it contained 37 "serious factual misrepresentations".
"You think you know better than Hungarians themselves", he said, and vowed that Hungary "will not accede to this blackmail".
Liberal MEP and former Belgian Prime Minister Guy Verhofstadt attacked Mr Orban, saying he was not his country and that Hungary was "far more eternal than you are".
Mr Verhofstadt also said it would be "impossible today" for Hungary to join the EU "under these circumstances".
But the MEP and former leader of the right-wing, Eurosceptic party UKIP Nigel Farage said both Mr Orban and his country had been insulted.
"Come join the Brexit club, you'll love it," he said. ■