"The staff had to lock all the doors to the recording studio and they manned the doors and refused to let anybody out. People were trying to storm out and leave and say, 'You can't stop me!' And they saying, 'Yes we can!'"
Denyer claimed that The Voice staff stood in front of the doors and blocked the exits and refused to let people leave before filming finished, a claim that a spokeswoman for The Voice has denied.
"It got so bad that audience members started ringing the cops," the radio star said on air. "They were calling triple-0 at the exits saying, 'I'm being held against my will at Studio 3 in Fox studios at The Voice set.'"
Denyer also revealed that he's heard the upcoming season of The Voice will feature a number of contestants who have already appeared on the Channel 9 show.
"There's rumours they're contacting a lot of previous contestants in the show, not a good sign," the Dancing with the Stars host said.
"If you can't find fresh talent and you're having to go back through previous series and ask people back on for another crack, that ain't looking that good."
2Day FM co-host Ed Kavalee added, "It's people you've seen before — they sucked last time, they suck again."
This year's coaches on The Voice are Delta Goodrem, Guy Sebastian, Kelly Rowland and Boy George.
In a statement to news.com.au, a spokeswoman for The Voice said: "The records for the Knockout round did run over, as often filming does, but no one was held against their will and was free to leave as soon as it was safe to do so.
"The studio doors were not locked nor were exits blocked. Our priority and responsibility is the safety of the audience and crew in a working studio."