The AFL and its 18 clubs have issued an unreserved apology for the sustained racism experienced by Indigenous AFL star Adam Goodes.

Key points: All clubs in the league have signed the apology

All clubs in the league have signed the apology The AFL's head of inclusion said it was a sincere apology, not "reputation management"

The AFL's head of inclusion said it was a sincere apology, not "reputation management" The statement comes as a film about Goodes's time as a player is released

Goodes's final three AFL seasons were overshadowed by continuous booing and racist slurs which sparked a vicious national debate about racism.

The apology comes ahead of the premiere of a film exploring the star's exit from the AFL at the Sydney Film Festival tonight.

The Final Quarter is a documentary made from archival footage of Goodes and the events that preceded his 2015 departure from football after the booing episodes.

Sorry, this audio has expired 'The AFL got it wrong'

In a joint statement, the AFL and 18 clubs stated the apology was issued on behalf of members, administrators, staff and players.

"Adam, who represents so much that is good and unique about our game, was subject to treatment that drove him from football. The game did not do enough to stand with him, and call it out," the statement said.

"We apologise unreservedly for our failures during this period.

"Failure to call out racism and not standing up for one of our own let down all Aboriginal and Torres Strait Islander players, past and present.

"Our game is about belonging. We want all Australians to feel they belong and that they have a stake in the game. We will not achieve this while racism and discrimination exists in our game."

The statement said the football community "pledged to continue to fight all forms of racism and discrimination, on and off the field".

"We will stand strongly with all in the football community who experience racism or discrimination.

"We are unified on this, and never want to see the mistakes of the past repeated."

Fans and the AFL community rallied behind Goodes in the wake of the booing. ( ABC )

'Really traumatic' for Goodes to watch documentary

Earlier this week, the documentary's director said the former Sydney Swans star found it "really traumatic" to relive the events when he watched the film.

Ian Darling said Goodes told him he would watch the documentary only once.

Darling said he felt the need to make the film in August 2015, when fans demonstrated an outpouring of support for Goodes with the #IStandWithAdam movement.

Part of the story explored by the documentary is a 2013 incident in which a 13-year-old girl called Goodes an "ape" during a game against Collingwood at the MCG.

He pointed to the girl after she made the comment and she was escorted from the grounds.

"In his press conference the next morning, about 17 times, he said 'It's not her fault, please don't go after her'," Darling said.

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The booing of Goodes intensified throughout the 2015 season, during which he performed an Indigenous war cry after kicking a goal in a game against Carlton.

His former teammate, Lewis Jetta, later said the booing was part of what had motivated the display of the dance, which was created during a development program with young Aboriginal footballers.

Sorry, this video has expired Goodes's war dance steals the show as the Swans beat Carlton

The film will not be released for distribution in Australian cinemas but the production company will make it freely available as an educational resource for Australian schools and sporting clubs.

It has been shown to AFL club executives and the Indigenous Players Advisory Board, which said many members left a screening earlier this year with "feelings of anger, shame and guilt but also a strong sense of pride and hope".

Sincere apology, not 'reputation management'

Tanya Hosch, the AFL's general manager of inclusion and social policy, told ABC Radio Melbourne that once the clubs had seen parts of the documentary, the "power of the film and what it lays out is undeniable".

"I think it's clear in the AFL, and Gillon [McLachlan] has previously acknowledged that the AFL got it wrong back when Adam was playing and these ugly things were happening," she said.

"[The film gave] us an opportunity to reflect and have a look, to really think about this again, and in many ways, it's another opportunity to focus on these issues in a way that is substantial.

"I'm very pleased that the 18 clubs in the AFL have been able to find some common ground on being very clear to say that we never want to see the mistakes of the past repeated in relation to what Adam endured."

Ms Hosch said the apology "doesn't change what Adam went through" but argued it was a sincere apology "rather than reputation management".

A second film on Goodes's departure, The Australian Dream, will premiere at the Melbourne International Film Festival in August.