The Supreme Court jury of nine women and three men found Martin, 54, of Claremont, guilty of having sexual intercourse with a person under the age of 17 years and of producing child exploitation material.

The jury was unable to reach a verdict in relation to a third charge of indecent assault.

Martin was a client of a 12-year-old girl who was prostituted in 2009 by her mother and Glenorchy man Gary Devine _ who have both been jailed for prostituting the girl.

After paying for sex with the girl in Devine's dimly-lit flat, Martin organised for her to visit him at his home for sex.

It was this visit that led to charges being laid.

During the visit Martin and the girl engaged in sexual activities and he took photographs of her posing sexually, for which she charged an extra $100.

The Crown argued Martin ought to have known the girl was younger than 17 but Martin told police during an interview played to the jury last week that he believed the girl to be 18 and that nothing in her behaviour or conversation suggested she was younger.

Five other clients of the girl also told the jury during the trial that they believed the girl was at least 18 years old but four of those men had only encountered the girl in Devine's flat.

During his police interview, Martin said medication he had been prescribed for Parkinson's disease had caused hypersexuality and had led to an addiction to prostitutes and pornography.

Justice Porter will hear sentencing submissions tomorrow afternoon and Martin _ who has been on bail since he was charged in 2009 _ was remanded in custody.

His lawyer, Peter Barker, said he would be seeking a non-custodial sentence on medical grounds.

He provided Justice Porter with two medical reports, one from a neurologist and one from a psychologist.

``In general terms both of those reports go to the issue of hypersexuality,'' he said.

Mr Barker said there was no risk of Martin re-offending.

``The hypersexuality has been addressed by a change in the medication,'' he said.

The jury began its deliberations at 10.30am today and just after 4pm the forewoman indicated to Justice Porter that jurors were having trouble reaching agreement on one of the counts.

He asked them to continue deliberations in case further discussion led to agreement but at 5pm the forewoman said there was no possibility of reaching a verdict in relation to that count.

The other two verdicts were by majority of 10 or more jurors.