Penrith star Nathan Cleary has labelled the racial abuse of Latrell Mitchell "disgusting", headlining a raft of big names calling for life bans for offenders.

South Sydney and NRL officials reiterated their support of Mitchell on Friday after a fan targeted him with a racist slur during Thursday's 16-10 loss at Penrith.

Vision from the tunnel at halftime showed several South Sydney players, including Cody Walker, pointing to a fan in a Sydney Roosters jersey and alleging they made the comment.

The fan is believed to have left the scene after making the comment but a man who was sitting with them - said to be the fan's father - was ejected by security.

A Biripi and Wiradjuri man, Mitchell has faced racial taunts in the past and in April 2021 two men were charged for sending him abusive social media messages.

Cleary, who has played alongside Mitchell at state and international level, was stunned by the incident.

"It's just disgusting," the Panthers halfback said.

"There's no point in a game where you should feel like you have the right to say stuff like that to a player.

"I hope they never come back here. They're not fans if they're saying that stuff."

In a statement, the Rugby League Players' Association backed the NRL's calls for alleged offenders to educate themselves on the impact of racist behaviour.

"While severe bans and punitive measures are important actions to take in response, there are also other solutions to help eradicate racism from sport and our country," the RLPA's statement read.

"The RLPA is supportive of a rehabilitative and educational response where people who say racist remarks or perpetuate racist behaviours are encouraged to learn about Australia's history, difference cultures and the potential impact of their actions."

Rabbitohs coach Jason Demetriou, club great Greg Inglis and Sydney Roosters mentor Trent Robinson have all called for life bans, while South Sydney chief executive Blake Solly said he was advocating the strongest possible action.

The issue went beyond rugby league on Friday, with federal opposition leader Peter Dutton throwing his support behind Mitchell and a life ban for any guilty fans.

Super-welterweight world-title hopeful Tim Tszyu also opened his press conference by backing his No Limit Boxing stablemate ahead of Sunday's fight against American Tony Harrison.

"I just want to say a shout out to Latrell," Tszyu said.

"There's no need for racism in any sport and let's keep it professional. Good on (him for speaking up).

"It's not good for sport, for any sport.

"There's no need to bring any of it, or politics or religion, stuff like that.

"We're just trying to keep it professional, and the way Latrell handled it was perfect."