In his submissions to the tribunal, the builder said the dogs had stayed around him and a co-worker most of the day without incident.
Shortly after lunch he noticed some streaks on the glass balustrade so decided to shoot home and grab some glass cleaner.
Both dogs were still lying on the deck when he went to his ute, closed the tailgate, and reversed down the driveway.
He stopped when he felt the ute hit something and looked out the window to see one of the dogs with her paw trapped under the right front wheel.
The builder moved the ute off and took the dog straight to a local vet clinic before ringing the owner and telling him to meet them there.
The dog underwent emergency surgery for what the vet described as a "catastrophic injury" and had to undergo months of treatment as well as further surgery.
Although the owner had pet insurance, it only covered $8000 of the total $21,000 in treatment, travel costs, and lost income that the owner tried to sue the builder for.
The tribunal said in its decision that the builder had a duty of care to supervise the dogs while the owners were absent.
By his own admission he said he should have secured the dogs inside the house before leaving and should have checked carefully before reversing his ute to make sure the dog wasn't anywhere near.
"If she had been standing behind the ute, he would, of course, have the usual duty of any driver to ensure that his path was clear behind him to reverse," tribunal referee Johanna Perfect said in her decision.
"However, for the dog's paw to be run over by the right front wheel, she was clearly low to the ground and out of his usual line of sight."
Perfect found that the builder had not breached his duty of care because he'd given a step-by-step account of how he'd gone and closed the tailgate and got into the car with no sign of the dog.
At the hearing, the owner said he'd told the builder to lock the dogs inside the house if he left the property.
However, Perfect found the builder hadn't been negligent in not locking the dogs up when he went to leave because his co-worker was still at the property and he'd left several times during the day without incident.
"It is natural in hindsight to look at events such as these, and point to what could have been done differently," she said.
"The standard of care that is being argued for in saying that he should have locked the dogs inside when he left site for a short time and his co-worker was remaining, is too high."
Perfect found that the builder's actions were not negligent and the owner's claim was dismissed.
