Some of the protesters who braved freezing cold weather to gather in the capital, Budapest on Sunday, carried European Union or Hungarian opposition party flags. Others carried banners that called Prime Minister Viktor Orban a "Viktator."

Opponents of the amendments approved by parliament last Monday are particularly disturbed by a change that would limit the power of Hungary's constitutional court. In future, the top court would only have the power to review the constitution or amendments on procedural grounds, not on substance. As well, all of its pre-2012 rulings would be rendered null and void.

Critics say the package of changes would reinstate a number of measures previously introduced by Orban's government, which were subsequently struck down by the constitutional court.

"On March 17, 2013 Hungary is not a dictatorship yet. But there is already an applicant for the job," Laszlo Majtenyi, a leading Hungarian lawyer told the rally.

"The basic components of democracy and constitutionality in Hungary have been broken," political activist and philosopher Gaspar Miklos Tamas said. "Hungarians want to live in a country in which the constitution is a joint work of the constitutional right-wing and the constitutional left-wing," he added.

Tamas also called on President Janos Ader to resign, after the head of state said earlier in the week that he had no choice but to sign the amendments into law.

Both the European Union and the United States have criticized the changes. The European Commission has assigned a team to examine Hungary's constitutional amendments to determine whether they comply with European Union law.

pfd/rc (Reuters, AFP)