'You f**king maggot!' - Australian Idol star Shannon Noll apologises after furious on stage rant

Warning: This story contains material that may offend some people.

Australian Idol star Shannon Noll has apologised after video of him unleashing a violent, expletive-filled rant on stage over the weekend was shared online.

Footage shows the singer/songwriter, referred to by many as 'Nollsy', becoming enraged after someone apparently threw an object at him during his performance at the Duck Creek Picnic Races.

"Hey, who's that f**khead? Get up here, man! Yeah, you - whoever threw that, get up here," Noll says in the video, pointing at someone in the audience.

"Have the balls to come up here and I'll meet you over there. That f**khead in the tie, everyone look around... come on, pretty boy. You f**king maggot! Come on, cheap shot prick. Hey, who says he should come up? Shame that prick! Shame that mother**ker right there!"

The outburst included Noll making a graphic threat of violence against the man, and a promise to have sexual intercourse with members of his family.

"F**king private school stupid f**khead mother**ker. Have some balls and get up here and I'll punch your f**king teeth down your throat, out the back. Dog arse prick. Then I'll f**k your missus and your mum."

The band continues playing music as Noll rages on. Just as he's about to continue the show, he gives one last message to the target of his rant.

"Righto, let's everybody have some fun - apart from that f**kstick," Noll says.

"I'll give someone $100 to punch that f**k for me... there's too many good looking girls here for you blokes. That c**t couldn't get a root in a f**king [unintelligible]."

On Sunday evening (local time), Noll took to his official Facebook page to say sorry for his actions.

"I would like to apologise for my behaviour and language at Saturday night's Duck Creek Picnic Races," says the singer.

"During our set there were people in the audience throwing cans and bottles at the stage and after one guy threw a full can, just missing my head it really rattled me.

"I completely understand that that is still no excuse for the way I spoke and I am deeply sorry for the terrible things I said that were purely out of frustration."

Australia's Nine News reports police are not investigating the incident.

Noll was the runner-up on the first season of Australian Idol in 2003, which Guy Sebastian won.