Thirteen channels ordered to be closed by the Venezuelan government went off the air on Saturday and more than 200 are expected to close in coming weeks.
The government broadcasting watchdog, Conatel, said that 34 radio outlets would be closed because they failed to comply with regulations.
However, critics claimed the crackdown infringed on freedom of speech and hundreds of protesters demonstrated in Caracas against the closures.
“They’re closing the space for dissidents in Venezuela,” William Echeverría, head of the National Council of Journalists, told RCTV, a private cable TV station, which did not have its broadcasting license renewed in 2007.
Mr Chavez defended the closures, calling them part of the government’s effort to democratise the airwaves.
“We haven’t closed any radio stations, we’ve applied the law,” he said on state television. “We’ve recovered a bunch of stations that were outside the law, that now belong to the people and not the bourgeoisie.”
Mr Chavez supporters say they are waging a “media war” against private news companies and have denounced in recent days what they say is a renewed offensive by privately owned domestic and international media to discredit Venezuela.