Ballard, who hosts ABC's satirical news program Tonightly, has vehemently denied the 'deeply distressing' account, insisting the encounter was entirely consensual.
The comedian said in a statement, 'I had absolutely no idea he believed it wasn’t consensual until six months ago.
'His version of that experience as described on social media is simply not what happened.'
Mr Roberts came forward with the account in a post to social media Saturday, claiming the pair met at an open mic night where Mr Roberts was performing at the time.
After talking at the hotel bar, Ballard invited Mr Roberts up to his hotel room, where Mr Roberts alleges Ballard kissed then fondled him.
'I thought he would give me some tips and share some advice [about comedy],' Mr Roberts said.
'I was unaware at the time he wanted to have sex with me.'
On the matter of expressing objections to Ballard's behaviour, Roberts told the paper: 'At the time I was scared, I’d only been doing stand-up comedy for a month.
'He was one of the more famous comedians in the country. I was inhibited.
'In the moment I didn’t want to cause offence to this guy. I wasn’t able to defend myself.
'Consent is trickier than [yes or no]. It’s got to be an enthusiastic yes.'
Mr Roberts said afterwards he reported the alleged assault to police, who claimed Ballard's actions were within 'the confines of the law.'
Mr Roberts encourages survivors of sexual assault to speak out and not be ashamed.
'If you tell the truth, all the right people will be on your side,' he said.
If you, or anyone you know, is seeking help contact Lifeline on 13 11 14 or visit lifeline.org.au.