West Coast ruckman Nic Naitanui has allegedly been the subject of racial abuse yet again, but more evidence is needed to catch the person who did it.

Naitanui was allegedly the subject of a racist taunt during Sunday’s western derby loss to Fremantle.

Domain Stadium – where the game was played – is investigating the incident.

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A crowd member allegedly shouted out the abuse from the eastern end of the stadium.

Another patron reported the verbal abuse to security staff, but they were unable to identify exactly where it came from.

West Coast midfielder Andrew Gaff said the club had a zero tolerance to racial abuse.

“It’s disappointing someone’s crossed the line,” Gaff said.

Naitanui, who is of Fijian descent, has been on the receiving end of racial abuse several times throughout his 111-game career.

In September 2011, Naitanui was targeted by rogue Collingwood fans at the MCG, with some shouting “tip rat” each time he got the ball.

“We have a zero tolerance policy around racial comments, at the club and the stadium. It’s disappointing that it’s occurred.” -AG

— West Coast Eagles (@WestCoastEagles) April 20, 2015

And earlier this year, a Perth man who allegedly racially abused Naitanui in a series of vile tweets was banned from contacting the AFL star or posting further racist comments on social media.

Naitanui has established himself as one of the AFL’s biggest stars since debuting in 2009, and he’s also one of the league’s multicultural ambassadors.

Meanwhile, Gaff concedes the team’s midfield need to lift after they were put to the sword against Fremantle on Sunday.

West Coast were thrashed 44-26 in the clearances, allowing Fremantle’s midfielders to run amok in the 30-point win.

“We were almost powerless when we couldn’t win the ball and they just kept pumping it into the forward 50 and kept scoring,” Gaff said.

“Every week the game’s won and lost in the midfield. It starts with us.

“If we win the ball and get it going forward, it puts the backs under less pressure.”

The Eagles face the winless Lions at the Gabba on Sunday, and Gaff is expecting a fierce encounter.

“Although they haven’t won a game, we know how quickly things can change,” Gaff said.

“They’ve got some quality mids – Dayne Beams, Allen Christensen, Daniel Rich, and all those guys.

“So we are under no illusions – it’s going to be a tough game.”

Lions skipper Tom Rockliff is a slim chance to make an early return from broken ribs and a punctured lung.

-AAP