Sean Penn has defended Hugo Chávez as a model democrat and said those who call him a dictator should be jailed.

The Oscar-winning actor and political activist accused the US media of smearing Venezuela's socialist president and called for journalists to be punished.

"Every day, this elected leader is called a dictator here, and we just accept it, and accept it. And this is mainstream media. There should be a bar by which one goes to prison for these kinds of lies."

Penn, who has visited Chávez in Caracas, said Venezuela's poor majority had willingly embraced his leftist revolution, but that this view was concealed from Americans.

"We are hypnotised by the media. Who do you know here who's gone through 14 of the most transparent elections on the globe, and has been elected democratically, as Hugo Chávez?"

Penn, speaking on Bill Maher's HBO chatshow, is part of a small but vocal pro-Chávez Hollywood group which includes Oliver Stone and Danny Glover.

They have remained steadfast even as Venezuela's leader has lost fans at home and abroad. Inflation, crime and water and electricity shortages have hit his popularity and led to defections from his socialist party.

The Organisation of American States recently accused Chávez of intolerance and authoritarianism, and a Spanish judge accused Venezuela of cosseting Farc and Eta terrorists, sparking a diplomatic spat with Madrid.

Chávez thanked Penn for his support in what he said was a daily battle for public opinion.

"I was reading the declarations from our friend Sean Penn, the famous American actor," he told a televised rally in Caracas. "Penn defended what he considers to be the truth."

The Hollywood star was an ally in the effort to counter a campaign to "confuse" Venezuelans, said the president, who has been in power for 11 years. "From here I thank you very much."

Other celebrity endorsements have come from the linguist and writer Noam Chomsky and model Naomi Campbell.