Brussels has threatened to launch legal action against Hungary if the Hungarian Parliament approves constitutional changes that critics say will limit citizens' freedoms.
The Hungarian parliament, which is controlled by the ruling center-right party Fidesz, is set to vote on the amendments on Monday.
The changes could affect higher education, electoral law and family law.
'Our job is to make sure that the EU law that member states have signed up to is complied with and of course we have legal instruments at our disposal to make sure that this is the case, I'm notably referring to out infringement proceedings and we will not hesitate to use all the instruments to make sure that member states comply with their legal obligations. This is the way that the Union works, it's based on the rule of law', said European Commission spokesperson Pia Ahrenkilde Hansen.
Thousands of Hungarians went on the streets of Budapest on Saturday to protest against what they see as a move to undermine the rule of law in the country.
During a phone call to Mr. Orban on Friday, EC's president Jose Manuel Barroso personally expressed his concerns over the new amendments and urged the Hungarian premier to respect the Union's democratic values.
'Prime Minister Orban reassured President Barroso that Hungary and his government are fully committed to EU values and EU law. (she says its on the letter orban sent barroso).(...) We will assess the result of the vote and respond', said European Commission spokesperson Pia Ahrenkilde Hansen.
Earlier this week, the Council of Europe, which is the EU's human rights watchdog, urged Budapest to postpone the vote, but the Hungarian authorities rejected the request.
Orban's political party came to power in 2010. The country has been surrounded by controversy since then.
