Films telling the stories of innovators in Africa have the power to transform the way people see the continent and drive social change, Oscar-nominated actor Chiwetel Ejiofor said on Friday.

Ejiofor's comments came as he appeared at Britain's leading conference on social entrepreneurship, the Skoll World Forum, to discuss his latest film, The Boy Who Harnessed the Wind".

The film, which he directed, starred in and for which he wrote the screenplay, is based on the true story of William Kamkwamba who helped save his Malawian village from drought by building a power-generating windmill from scrap.

Highlighting young people who identify and find solutions to local problems was important to encourage social businesses, said Ejiofor, who won a BAFTA award and Oscar nod for playing Solomon Northup in the Oscar-winning film "12 Years a Slave".

"Telling authentic stories about who people are, not just what they are, will enrich the cultural space in a very radical way," he said on the final day of the four-day forum in Oxford.

The Boy Who Harnessed the Wind was partly financed by Participant Media, a U.S. film company that aims to advance social missions through movies, and launched on Netflix in 2019.

Participant was founded in 2004 by billionaire and former eBay president Jeff Skoll, who set up Skoll World Forum, and is behind the Academy Award-winning film Roma which tells the story of an indigenous Mexican domestic worker.

Social entrepreneurs typically tackle social and environmental problems with commercial strategies.

The sector has grown significantly in the past decade although there is no comprehensive data to show the size of the social enterprise sector across Africa.

There are about 26,000 social enterprises in Ghana and 40,000 in Kenya, according to 2016 estimates by the British Council, a partly state-funded body that promotes British culture overseas. Ejiofor, 41, who was born in London to Nigerian parents, said he believed the film industry was at a tipping point where more movies that aim to change perceptions and deliver social impact will be made.

"It has taken a bit of time to get to a point whereby we can really start to engage with stories like this, but I feel like we are really on the cusp of being able to do that in an aggressive and a more open way," he said.