South American trade bloc Mercosur called for "free, fair and transparent presidential elections, as soon as possible" in Venezuela, at its summit in Argentina on Wednesday.
The presidents of the four member countries signed a statement expressing concern "for the grave crisis that Venezuela is going through, which is seriously affecting the humanitarian situation and human rights."
New presidential elections are a key demand of Venezuela's opposition led by National Assembly leader Juan Guaido.
Representatives of the government and opposition are currently meeting in Barbados for talks mediated by Norway on ending the country's political crisis.
Venezuela has been in turmoil since Guaido, quickly backed by more than 50 countries, declared himself acting president in January and branded socialist leader Nicolas Maduro a usurper over his 2018 re-election in a poll widely viewed as rigged.
Three of Mercosur's members -- Brazil, Argentina and Paraguay -- have backed Guaido, while only Uruguay, under a socialist government, has not done so.
Brazil's far right President Jair Bolsonaro hit out at Maduro's leftist regime, as he took over Mercosur's leadership reins.
"We don't want what's unfortunately happening in Venezuela to happen in any more countries," said Bolsonaro at the summit in the northeastern city of Santa Fe.
"How can a country as rich as Venezuela arrive at the point it has? We know how it was born: populism and the irresponsibility of a party with no limits," added the president, widely regarded himself as a right-wing populist, in an attack on Maduro's United Socialist Party of Venezuela.
Venezuela is wracked by an economic crisis after five years of crippling recession in which its population has faced many hardships such as a shortage of basic necessities and failing public services.
The country was once part of the Mercosur bloc but was suspended in 2016 over concerns about human rights violations and a failure to respect democratic values or the bloc's commercial obligations.
"There's no more space between us for authoritarian regimes," said Bolsonaro, who has in the past expressed his admiration for Brazil's 1964-85 dictatorship and its use of torture against left-wing opponents.