The sentence handed to the juvenile killer of south-east Queensland woman Emma Lovell has been reduced on appeal.

Last year, a 20-year-old man pleaded guilty to her murder, admitting to stabbing her on her front lawn in 2022.

He was sentenced to 14 years in detention and was ordered to serve 70 per cent of that in custody.

A man and woman taking a selfie on a beach.

Emma Lovell was murdered and Lee Lovell was injured during the North Lakes home invasion in December, 2022. (Facebook: Lee Lovell)

When he was 17 years old, he broke into her North Lakes home late on Boxing Day night, and during a struggle with her and her husband Lee, he wounded them both.

In June, he challenged his sentence, arguing it was manifestly excessive.

On Friday the Court of Appeal ruled in his favour and granted the appeal.

His sentence was varied, and he will now be released after serving 60 per cent of his 14-year term.