TWO prisoners, defending themselves against allegations of torturing their former cellmate and forcing him to perform sexual acts, took turns to grill their 22-year-old victim from the dock on Tuesday.

The first, Iryan Abdul Karim, 21, holding a bundle of documents in his hands, continued his systematic questioning, which began on Monday afternoon, before challenging the victim's version of events.

The second, Muhammad Hamdan Abdul Rahman, 20, launched his cross-examination with a speech accusing the victim of telling lies to seek revenge.

At one point, Hamdan was told by High Court judge Tay Yong Kwang that it was pointless to argue and he should put his case to the victim instead.

The two, together with Mohammed Zameen Abdul Manoff, 21, face multiple charges of physically and sexually assaulting the victim in their Changi Prison cell between April 27 and May 4 last year.

The victim, who cannot be named under a court order, was hospitalised for two months.

In general, the trio have admitted beating up their former cellmate. But they dispute parts of his account and maintain that he was a willing party in the sexual acts.

'I'm not claiming innocence, neither am I guilty of all the charges that you are accusing me of,' said Hamdan on Tuesday as he accused the victim of exaggerating and fabricating statements.

But the victim did not waver from his account.

Zameen is expected to cross-examine the victim on Wednesday.