Polish director Agnieszka Holland said Tuesday she wanted to "change the world" with her latest film, "Green Border", about migrants stranded on the Polish-Belarusian border.

The harrowing black-and-white film won a Special Jury Prize at the Venice film festival last month but also brought scorn and even death threats to its 74-year-old director.

Poland's populist government built a razor-wire fence along its border with Belarus in 2022 to deter illegal migrant crossings that it says were orchestrated by Minsk.

The measure has reaped criticism among rights organizations as Poland refused to let the refugees in.

"Green Border" tells the story of migrants, border guards and volunteers, using real-life experiences.

"The film was necessary as people felt this should be discussed, that we should ask ourselves who we are and what humanity means," Holland told reporters in Prague.

"I wanted to change the world" with the film, Holland said in fluent Czech she had picked up during studies at Prague's Film Academy in the late 1960s.

Holland, who was nominated for Oscar twice, said she had spent a week in the company of two bodyguards, following death threats as "Green Border" was due to hit Polish cinemas in September.

She also faced hate speech from top politicians from the ruling Law and Justice (PiS) party, which she calls "Lawlessness and Injustice".

"The attacks on me were insane, something I have never experienced although I lived in communist Poland," Holland added.

Top officials likened her to Adolf Hitler, Joseph Goebbels and Joseph Stalin and told her she "wasn't Polish and should get out of Poland".

But Holland said Poles in general received the film well as she toured the country to present it.

"People cried, they stood up and applauded even in small cinemas," she said, adding the film worked as "collective psychotherapy" in the affected eastern regions.

PiS won Poland's general election on Sunday, but the pro-European opposition is likely to oust it from power after eight years as it secured a parliamentary majority.

Holland said she expected the mood in Poland to change, although "it will take time".

"But I won't be using bodyguards for the rest of my life," chuckled Holland, who is now planning a film about the Prague-born, German-writing author Franz Kafka.

"When I came to Prague to study, I was a Kafka fan. My first walks here were in his footsteps," Holland said.