A woman whose dog mauled her three-year-old grandson to death then taunted her own son at his child's funeral - and he retaliated by trying to kill her.

Korbin Sprott was killed by his grandmother's German Shepherd when the dog attacked him in her backyard in Mackay, Queensland in 2013.

Korbin's father James Sprott, 30, had pleaded with his mother Sonia Strachan to have the dog put down after it bit the child a year earlier.

Ms Strachan taunted her son at Korbin's funeral, and so he retaliated by going to her house, smashing her face with a beer bottle before trying to break her neck and kill her, a judgment released on Friday has revealed.

Korbin Sprott (pictured with his father James) was killed by his grandmother's German Shepherd when the dog attacked him in her backyard in Mackay, Queensland in 2013

Korbin's father James Sprott had pleaded with his mother Sonia Strachan to have the dog put down after it bit the child a year earlier

Sonia Strachan's German Shepherd grabbed her grandson by the neck in the front yard of her Mackay, North Queensland, home in 2013 (stock photo)

James Sprott had lived with his mother after his marriage ended but their relationship soured when he asked her to have her dog euthanised.

He pleaded with his ex-wife not to leave his son in the care of his mother and her dog, but she ignored him.

The dog killed Korbin in 2013, but Sprott was not told of his son's death until some time later when a relative living in the United Kingdom called him.

At Korbin's funeral, Ms Strachan and her boyfriend Mark Gallagher sat behind Sprott and taunted him.

'I'm going to sit here, you c**ts,' she said, before calling her son a 'dog' and a 'useless c**t', according to the judgment.

On April 11, 2017, about four years after his son's death, Sprott went to his mother's house while holding two beer bottles.

He smashed one of the bottles into his mother's face before grabbing her head from behind in an attempt to break her neck.

Sprott then punched Mr Gallagher in the face and stomped on his head.

He turned back to Ms Strachan and threw her on the floor, then into a TV cabinet, then picked up a pot plant and slammed it onto her face as she tried to crawl away on her back.

At Korbin's (pictured) funeral, Ms Strachan and her boyfriend Mark Gallagher sat behind Sprott and taunted him

A neighbour, Mitchell Thompson, heard the attack and raced over to see Sprott punching his mother hard in the face about five times.

'Help me, he's going to kill me,' she cried, according to the judgment.

Thompson punched Sprott in the face, knocking him out.

Sprott later told police he wanted to kill his mother and Mr Gallagher.

Sprott pleaded guilty to two counts of attempted murder and was originally sentenced to two concurrent sentences of nine-and-a-half years.

Queensland Attorney-General Yvette D'Ath appealed Sprott's sentence, saying it was inadequate, but the Queensland Court of Appeal disagreed.

The judge in the original case was found to have been justified in giving Sprott a lenient sentence due to the poor treatment he received from his mother while growing up.

The dog killed Korbin in 2013, but Sprott was not told of son's death until some time later when a relative living in the United Kingdom called him

'In particular, the respondent's state of health was caused in part by his mother's lifelong neglect of him, and was greatly contributed to by both of his victims' irresponsibility that had led to the little boy's death, and by their almost incredible callousness afterwards,' the judgment said.

'While the sentences are outside the general range, so too are the facts of this case outside the usual run of cases.'

The appeal to lengthen Sprott's jail sentence was dismissed, and he will be due for release in 2026.