A food stall assistant sentenced to 23½ years' jail and 24 strokes of the cane last year for sexually abusing his daughter has found two friends who are willing to corroborate his claim of misshapen genitalia, a key element of his defence at his trial.

The Court of Appeal has sent his case back to the trial judge to determine the veracity of the new evidence, before his appeal hearing can continue.

The 42-year-old appellant had argued it was highly improbable for him to be able to perform penetrative acts on his daughter because of his deformed penis, the result of a botched enlargement procedure.

He claimed it became deformed in 2009 but the prosecution contended that the physical changes occurred only after the offences. The girl and her mother had testified that his penis looked normal even in April 2014.

Yesterday, in his appeal against conviction, the appellant, who cannot be named to protect his daughter's identity, tried to admit an affidavit made by one of the two friends.

In the affidavit, Mr Muhammad Ridzwan Idris said he had seen his friend's penis in 2013 while they were in the toilet. He said it "did not look normal".

The other friend, Mr Mohamed Alwan, had earlier backed out of filing an affidavit, purportedly because his wife did not want him to get involved.

The prosecution said it found the new evidence "incredible and suspect".

"In the span of three short weeks... the appellant met two different people who, by sheer stroke of coincidence, were both able to testify to the deformed state of his penis at the time of the offences," said Deputy Public Prosecutor Mohamed Faizal.

With the case going back before the trial judge, Mr Ridzwan will be cross-examined on his account and the appellant will have to explain how he found these two witnesses.

Chief Justice Sundaresh Menon said the prosecution's concern - that the appellant was introducing "fake evidence" to get himself off the hook - was a legitimate one. If this was indeed the case, the man will face the "full scale of the law", he said.

However, he added that the court - which also comprised Judges of Appeal Andrew Phang and Tay Yong Kwang - cannot come to such a conclusion without hearing the evidence of the relevant witnesses. The appellant had claimed trial to 10 counts of various sexual offences committed against his daughter between the end of 2011 and April 2014, when she was aged between 11 and 13.

On Thursday, DPP Faizal argued that the circumstances leading to Mr Ridzwan coming forward were dubious.

The appeal was initially scheduled to be heard on Jan 19, but that day, the appellant sought an adjournment, apparently having come across Mr Mohamed three days earlier, who offered to testify. But Mr Mohamed purportedly backed out on Jan 31.

On Feb 3, the appellant said he chanced upon Mr Ridzwan and told him about Mr Mohamed bailing on him. Mr Ridzwan allegedly told his friend he could back up his claim and even offered sketches of his genitalia from two different angles.

The appellant's lawyer, Mr Ramesh Tiwary, argued that before meeting Mr Ridzwan on Feb 3, his client did not know that his friend had seen his penis before.