Soundgarden singer Chris Cornell reportedly called Kanye West "retarded" as the Big Day Out's headlining acts faced off against each other at the Gold Coast Big Day Out.
Reports have emerged of a growing spat between the two acts after West's soundcheck on a neighbouring stage drowned out part of Soundgarden's set during the Sunday leg of the touring Australasian festival.
Soundgarden's fans booed when West's sound check interfered with their performance.
Cornell reportedly told the crowd: "Sounds like there's children playing music there, retarded children, retarded as in held back ... There's no other word for it."
That wasn't the only problem on the night. Big Day Out organisers were quick to point out that a 45-minute delay in the start of West's performance was caused by equipment damage following a sudden storm.
In a statement, the festival's management said despite the delay the hip-hop star delivered a 90-minute performance that the audience were happy to hang around for.
The Gold Coast Bulletin reported fans were vocal in their protests while waiting for West to take the stage.
But BDO promoter Ken West was quick to defend the delay and the subsequent performance.
"The fact that he had the biggest crowd of the day and delivered an incredible performance with the huge crowd staying to the end of the set, even though it was 45 minutes later than scheduled, is a testament to what a great artist he is,'' Mr West said.
West is only playing three of the six Big Day Out festivals after organisers scaled back shows in Auckland, Adelaide and Perth.
This was the last year the Big Day Out was held in New Zealand.