BERLIN - Veteran Polish filmmaker Andrej Wajda said Friday he was planning a biopic on "national hero" Lech Walesa, intended to defend him against "attacks" by political rivals.

Wajda, unveiling a moving new drama in competition at the 59th Berlin Film Festival, said it was time 20 years after the fall of the Berlin Wall and the end of Polish communism to pay the former Solidarity leader and ex-president his due.

"Walesa is our national hero, irrespective of the mistakes he made when he was in office," he said

"I can remember the Berlin Wall, I can remember the barbed wire. The fact that we are here today coming from a free country is in large part thanks to him."

Walesa founded the Soviet bloc's first independent trade union, Solidarity, which was instrumental in hastening the end of Polish communism and served as Poland's first democratically-elected, postwar president from 1990 to 1995.

Wajda said that despite Walesa's errors, his reputation was being unfairly dragged through the mud by political opponents.

"Now rumours and lies are being told," he said in a veiled reference to Walesa's bitter falling-out with President Lech Kaczynski and his twin brother, former prime minister Jaroslaw Kaczynski.

"Walesa is my friend and when he is under attack and I as a Polish director have the tools to communicate with a large audience that is what I'll do."

Walesa, who was in Brussels Wednesday for an EU meeting considering the way ahead for Europe, told Polish journalists that Wajda was the only director he would trust with a film biography, saying he understood Poland.

Asked what the film should be called the Nobel peace laureate replied: "Lech and Danuta," referring to his wife.

Previous attempts to make a biographical film failed, he said, partly because they tried to spice up the romantic side. "I didn't agree," he said.

Wajda, whose drama "Katyn" about a 1940 massacre of Polish officers by Soviet secret police was nominated for an Oscar last year, has been making films for five decades.

His Cold War masterpieces offered unflinching looks at communist oppression and then the budding Solidarity movement -- pictures including "Man of Marble" and "Man of Iron," which featured Walesa himself.

He thanked the Berlinale, as the festival is known, for its unswerving support when he was facing intense political pressure at home.

"The Berlin Film Festival is somewhere where I've always been very, very fortunate," he said, adding that many of his films which were not distributed at home during the Cold War were launched to the rest of the world from the divided German city.

"I'm very pleased that the festival director, Dieter Kosslick, found place for an old director."

Wajda's innovative new drama "Sweet Rush" tells the story of a lonely doctor's wife in the 1950s whose lost hopes for life are reawakened when she meets a much younger man.

The film weaves in scenes written and read out by his lead actress, theatre legend Krystyna Janda, after the death of her husband, Wajda cinematographer Edward Klosinski, during the making of the picture.

"Sweet Rush" is one of 18 films vying for the Berlinale's coveted Golden Bear top prize, to be awarded Saturday night. The festival wraps up Sunday.