Thousands in Argentina marched through the capital Buenos Aires chanting slogans, banging pots and pans and waving banners against the government of President Cristina Fernandez de Kirchner.
The protest was triggered by a government proposal to reform the judiciary but people also showed their discontent over high inflation and crime.
Many protesters reported that they were angry at a proposed government bill that would allow voters to choose the magistrates who appoint and remove judges.
The Argentine opposition has criticised the move saying it would politicise the judiciary.
Opposition activists used social networks to mobilise the march, which was the biggest since November.
There has been no comment so far from the Argentine government.
President Fernandez left the country on Thursday to attend a summit in Peru.
However, correspondents say there will be concern in government quarters that the opposition might take strength from this protest with crucial legislative elections later this year.
“I came to see if the Kirchners will leave and that peace returns so that we can be a united country once again,” said Lorenzo Velazquez, a 51-year-old food worker in Buenos Aires.
He carried a sign saying “2015 Sin Cristina” referring to the year when President Fernandez’s current term will end.