A WARWICK man found guilty of molesting an underage girl has had his appeal against the conviction dismissed.

The 73-year-old man, who cannot be named to protect the identity of his victim, was last year found guilty of both maintaining a sexual relationship with, and the indecent treatment of a child under 16.

He appealed the decision, claiming the verdict was unreasonable.

The appeal was dismissed last Friday in the Brisbane Court of Appeal.

During a four-day trial in the Toowoomba District Court in October last year, the court heard the man had molested the girl on about 25 occasions during a period of three years.

The young girl had grown up riding horses on the man's property and he had later taken her away to horse events.

It is during these trips and while the pair were exercising the animals that the man touched her indecently.

She was aged between 11 and 14 years during the span of the abuse.

The victim told police there were "so many" incidents of touching she couldn't put a time or date on each instance, and "he did something" almost every time they were alone together.

The young woman, who was 18 at the time of the trial, said the man put his hands down her shirt, squeezed her breasts and rubbed the outside of her jeans, near her pubic area.

Despite the abuse, the girl said she was too scared to tell anyone what had happened to her.

She finally revealed the abuse to her parents during a "heat-of-the-moment argument" in 2012 and a report was made to police in 2014.

The jury took less than an hour to return a guilty verdict.

The Warwick man was sentenced to 18 months jail, suspended after serving four months behind bars.