Australian singer Shannon Noll has apologised after an expletive-laden rant in which he threatened to punch a concertgoer at a gig in rural NSW.

Footage emerged of the former Australian Idol runner-up on Facebook on Sunday performing at the Duck Creek Picnic Races in Nyngan on Saturday.

His set was interrupted when a member of the crowd threw a beer can onstage, calling Noll a “f–––head”.

“Come on then, that f–––head in the tie. You’re a f–––ing maggot. Have some f–––ing balls to come up here instead of throwing something from there … Come on, cheapshot prick,” Noll yelled as the band prepared to play Daryl Braithwaite’s The Horses.

The What About Me singer also incited the crowd to shame that mother–––––– there” and offered $100 for someone to “punch that f––– for me”.

“F–––ing private school, stupid f–––ing mother–––––– … Have some balls and come up here and I’ll punch your f–––––– teeth down your throat out the back, dog-arse prick. Then I’ll –––– your missus and your mum,” he said.

“Alright, enough with the haters, f––– the haters. There’s too many good-looking girls here for you blokes.”

The two-minute long rant went viral with almost one million hits in a 24-hour period.

Noll on Sunday night posted an apology on his Facebook page, saying he reacted “purely out of frustration”.

“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,” he wrote.

“We had a similar issue last year with a firecracker thrown onto the stage and one of my band members was seriously hurt … you don’t have a lot of deep vision into the crowd from the stage and it’s pretty scary to see something suddenly flying straight at you.

“We’re just doing our job and these actions are not acceptable.

“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.