Demonstrators carrying Venezuelan flags rode in motorcycle convoys through the streets of several cities, videos showed.
Machado has been unable to return to Venezuela since travelling to Oslo in December to receive the Nobel Peace Prize. The opposition politician, who is currently in Panama, has so far made seven unsuccessful attempts to return, according to media reports.
Supporters of the opposition parties Vente Venezuela and Primero Justicia were among those taking part in the demonstrations.
Protesters called for a clear timetable for presidential elections in 2027 and chanted slogans including "Freedom, freedom!"
A few weeks after Machado secretly left Venezuela, US forces captured authoritarian leader Nicolás Maduro during a military operation in Caracas in January.
Since then, the country has been led by acting President Delcy Rodríguez, who has worked closely with Washington.
Rodríguez served as Maduro's vice president and is regarded by the opposition as part of the country's previous authoritarian system.
Opposition politician and former political prisoner Juan Pablo Guanipa joined demonstrations in the western city of Maracaibo.
"We are on the streets of Maracaibo demanding the return of María Corina Machado, immediate free elections and the release of all political prisoners," Guanipa said in a video.
Hundreds of people have been released from detention in Venezuela in recent months.
Human rights organisations said around 30 more people were freed on Friday evening, just days after the first meeting between US President Donald Trump and Rodríguez on the sidelines of the UN General Assembly in New York.
According to the Venezuelan human rights organisation Foro Penal, more than 300 political prisoners remain in detention.
10°C