Brendon Toohey, 40, was sentenced in the Parramatta District Court on March 7 in a judge-alone trial before Judge Bennett.

Toohey entered a plea of not guilty to the charge, with Judge Bennett returning a guilty verdict on the day.

In 2017, Toohey was convicted of the manslaughter of the same 11-month-old infant and was jailed for seven-and-a-half years, however, a non-parole period of four-and-a-half years made him eligible for parole on October 8 last year.

A second charge of sexual intercourse with a person under 10, under authority, was heard separately from the manslaughter charge.

On the sexual assault charge Toohey was convicted and sentenced to a jail term of four years and six months (three years non-parole), to date from March 9, 2016, making Toohey eligible for parole on March 8, 2019 - the day after he was sentenced.

The maximum period of four years and six months expires on September 8, 2020.

Toohey was charged by police in the weeks following the infant's death in 2014 and has remained in custody since his arrest.

Toohey had always maintained that the baby girl suffered critical injuries when she fell from a trampoline and hit her head on the lid of a concrete septic tank as he was taking clothes off the washing line at a Mandurama home.

At 11am on April 2, 2014, Toohey arrived at the emergency department at Blayney Hospital but, despite treatment, the baby was declared dead at 12.40pm.

Strike Force Zarebski was established to investigate the incident and Toohey was subsequently charged with murder. He was found not guilty by a 12-person jury in July 2017 who then delivered a guilty verdict for the child's manslaughter.

In returning a guilty verdict in the sexual assault matter, Judge Bennett convicted the offender but made a finding of special circumstances. He said parole would be supervised, and would be a matter for the parole authorities.