"For decades, our coverage was racist" reads the forthright headline for National Geographic as the iconic magazine looks back at its coverage of people of colour.

National Geographic called on University of Virginia professor Jason Mason to examine its history of covering people of colour in Australia, the US and around the world.

The magazine wanted to examine how it had presented race throughout its history to rise above its past.

Prof Mason, a professor of African history, said the magazine failed to acknowledge people of colour in the US, outside of labourers and domestic workers, in its early issues.

National Geographic editor-in-chief Susan Goldberg, the magazine's first female editor, described the historic coverage as "appalling".

Prof Mason said early publications up until the 1970s "did little to push its readers beyond the stereotypes ingrained in white American culture".

This included ignoring people of colour in the US and picturing "natives" abroad as "unclothed, happy hunters, noble savages - every type of cliche", and its reporting of Australia's Indigenous people - where a photo in a 1916 article depicted them as "savages".

Our April issue is devoted to exploring race—how it defines, separates and unites us. Read the story behind the cover: https://t.co/PPTVg3UpM8 pic.twitter.com/5kunxfDrHt — National Geographic (@NatGeo) March 12, 2018

AAP

"Some of what you find in our archives leaves you speechless, like a 1916 story about Australia. Underneath photos of two Aboriginal people, the caption reads: "South Australian Blackfellows: These savages rank lowest in intelligence of all human beings".

The exploration of National Geographic's coverage of race discusses the reporting of a massacre in South Africa in 1962 that left 69 black South Africans dead in a police shooting in Sharpeville.

The reporting barely mentioned any problems, according to Prof Mason, and did not give a voice to black South Africans.

This is in stark contrast to a piece in South Africa, published more than a decade later in 1977, which acknowledged the oppression of black South Africans.

The article shows how the publication was, for many people, a gateway to the world and continues to break down barriers using a diverse group of writers, editors and photographers to uncover untold stories.

AFP

Goldberg said the magazine had a duty to portray authentic views of the world, noting National Geographic had a heightened sense of responsibility when reporting on race.

"So let's talk about what's working when it comes to race, and what isn't ... Let's confront today's shameful use of racism as a political strategy and prove we are better than this," she writes.

The April race issue is a special issue of National Geographic that explores how racism has divided and united society throughout history.