BRISBANE forward Charlie Cameron is the latest target of racial abuse as a league investigation widens to include three clubs expressing disgust at vilification.

The AFL's integrity unit is now probing cases of racist slurs directed at Cameron, Fremantle's Michael Walters and Nathan Wilson, and Adelaide's Izak Rankine.

All four Indigenous players were vilified on social media in the past two days.

"This has to stop," AFL chief executive Gillon McLachlan said on Tuesday night.

"It not only hurts the Aboriginal and Torres Strait Islander players targeted but all Indigenous players and players of colour across the league as well as their families, their teammates and friends.

"There is no place in our game for anyone who vilifies our players."

STATEMENT AFL CEO Gillon McLachlan condemns remarks

Brisbane's chief executive Greg Swann reported the abuse of Cameron to AFL hierarchy on a day when Fremantle and Adelaide expressed disgust at their players being racially vilified.

"I'm angry and disappointed that Charlie, and we as a footy club as well as an industry, have to constantly deal with this," Swann said in a statement on Tuesday night.

"It's cowardly behaviour, hiding behind social media and abusing and attacking our players."

A Brisbane supporter saw racial abuse directed on Cameron on social media and reported it to authorities.

The Brisbane statement came just hours after Fremantle's chief executive officer Simon Garlick detailed racist and homophobic abuse of Walters and Wilson.

The incident involving the Dockers came a day after Adelaide's recruit Izak Rankine reported being racially abused on social media.

And the latest cases come only two weeks after Western Bulldogs forward Jamarra Ugle-Hagan was racially abused by a spectator and also online.

"This unnecessary and disgusting abuse should not happen and it saddens me, and everyone at our club, that it does," Fremantle's Garlick said in a statement.

"Individuals that hide behind fake accounts to hurt others are pathetic and we need to be able to curb this capability on social platforms.

"Enough is enough."

Earlier Tuesday, Adelaide's coach Matthew Nicks branded abuse of Rankine as a "cowardly act".

"It's just someone who is trying to hurt," Nicks told reporters.

"If someone is going to the trouble of covering up their identity, it's not an actual account, it's never been used - to me that's a sign that we're not actually dealing with a human being, we are dealing with someone who is just trying to be divisive."

Rankine's teammates and Crows staff have rallied around the goalsneak, who returned to South Australia this season after spending three years at Gold Coast.

"He has got 100 per cent support from everyone at the footy club," Nicks said.

"Things like this can bind you, a group come together, and we were able to show our support."