The film by British director Michael Winterbottom, starring Steve Coogan, takes aim at high-flying moguls whose lavish lifestyles, yachts and parties are built on sweatshop labor.

"The extreme wealth (that) Greed's main character accumulates at the expense of exploited workers is not as far removed from us at it seems," said Joanna Ewart-James, executive director of anti-slavery organization Freedom United.

"Our own bulging wardrobes indicate how this has become an almost $3 trillion industry, lining the pockets of big business and not the 60 million-plus garment workers - who earn as little at $21 a month," she told the Thomson Reuters Foundation.

Campaigners said they hoped the film would draw attention to the stark contrast between the lives of fashion retail owners and their staff - and encourage consumers to think more carefully about their choices.

The advent of fast fashion, with consumers buying and quickly binning cheap clothes, has exacerbated the risk of forced labor in global supply chains as factories come under ever greater pressure from leading brands, activists say.

Director Winterbottom said his inspiration for the film came from a conversation about the "colorful character" of British billionaire Philip Green, whose Arcadia group owns a string of fashion chains including Topshop.

Green's greed and disregard for corporate governance led to the demise of British high street store BHS and cost 11,000 jobs, British lawmakers said in 2016, calling the collapse "the unacceptable face of capitalism".

Coogan's character also faces parliamentary scrutiny over his business dealings and throws an extravagant party on a Greek island - echoing Green's infamous multi-million dollar birthday celebrations attended by A-list actors, models and popstars.

Read also: Fast fashion hurts workers and the environment, British lawmakers told

"We're using the likes of Philip Green to raise the subject of this kind of exploitative slave labour that makes people rich," said British actor and comedian, Coogan, who is best known for his television character Alan Partridge.

"People involved in this world, they sleep like babies. It doesn't bother them," Coogan said, describing how surreal it was to shoot on a luxury yacht and then in a Sri Lankan garment factory where people earned $4 a day.

Green was not immediately available to comment.

Comedian David Mitchell, who plays a journalist in Greed, said filming in garment workers' homes with "no plumbing and very little space" was a memorable experience.

"It's a pretty grim place to live," he said. "And obviously that's all about the rate of pay, which is dictated by market forces unrestrained by governments."

Jakub Sobik of Anti-Slavery International said films like Greed were important in highlighting the exploitation of vulnerable workers in the fashion industry.

"They could play a big role in making people aware of the problem and demanding better from businesses and governments," he said.

About 25 million people are estimated to be trapped in forced labor, the United Nations says.