Speaking on 2Day FM's breakfast show yesterday, the Gold Logie winner claimed one person had called the police to alert them to the situation unfolding at Sydney's Fox Studios.
A member of the audience subsequently rang in to Triple M's Kennedy Molloy and confirmed much of Grants accusations, branding the experience "traumatising".
"It was pretty traumatising by the time we finished - we got there at 2 o'clock, it was supposed to until 7.30pm and at 10.30pm walked out and it was still going," he said revealed.
The caller further revealed guests were given little food and had to make do with "a bottle of water and a packet of chips".
The Voice Australia issued a statement in response, saying:
"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.”
The spokeswoman further added no police were called to the set.