The presiding judge in the child sex trial of Brisbane man Max Sica has adjourned the hearing to consider his verdicts.

42-year-old Sica, who is already serving a minimum non-parole period of 35 years for the murders of the three Singh siblings in 2003, is accused of more than 20 child sex offences.

It is alleged he had a sexual relationship with a girl, which started in 2004 when she was nine years old.

Sica won the right to a judge-only trial due to his notoriety for the Singh murders.

Judge Michael Shanahan says he expects to deliver his verdicts within the next fortnight.