Chilean dictator Augusto Pinochet and British prime minister Margaret Thatcher were reimagined as soulless vampires in a biting satire that premiered at the Venice Film Festival on Thursday.

Netflix movie "El Conde" depicts Pinochet, who ruled Chile as the head of a brutal military junta from 1973 to 1990, as a vampire sating his bloodlust by cutting out hearts and sticking them in a food blender.

The film is narrated with the unmistakeable voice of Thatcher, the right-wing British prime minister who was a close ally of Pinochet during his rule.

"El Conde", one of 23 films competing for the Golden Lion in Venice, was directed by Chile's Pablo Larrain, who has became an international star with biopics of Jackie Kennedy ("Jackie") and Princess Diana ("Spencer").

"There was a whole process to find the best way to approach (Pinochet). He's never been portrayed before, either in cinema or television," Larrain told reporters in Venice.

"The combination of farce and satire... was probably the only way. If you avoided the satire, it could easily take you to some form of empathy and that's not acceptable," he added.

He chose to depict him as a vampire because Pinochet "never really faced justice", said Larrain.

"He lived and died in freedom and actually quite rich. That impunity made him infernal."

Pinochet was a military general who overthrew the left-wing government in 1973, overseeing thousands of executions of political opponents and a vast programme of detention, torture and corruption.

He was supported by the United States, and an ally of Thatcher during Britain's war with Argentina in the 1980s.

Larrain praised Netflix for funding the film, which will be available to stream from September 15.

"I think it's wonderful that Netflix can support a movie like this that is bold and unique," he said.

Critics gave it a mixed response at Venice, however.

While The Hollywood Reporter called it "bracingly original" and "darkly funny", Screen Daily felt it "lacks bite" and felt too "high-concept: an elevator pitch to Netflix HQ".