Toddler Mason Jet Lee was treated callously in the lead up to his death and received no basic care or tenderness, a court has been told.
Queensland Attorney-General Yvette D'Ath is appealing for more jail time for the pair who killed the 22-month-old - his mother and her then partner.
Anne Maree Lee and William Andrew O'Sullivan pleaded guilty to Mason's manslaughter after failing to get him medical treatment as he suffered an agonising death in June 2016.
The pair were also convicted of child cruelty after not seeking help for his leg and anus injuries about five months before his death.
"This young child was dealt with in a callous manner," barrister Michael Byrne QC for Ms D'Ath told the Court of Appeal on Friday.
"There was an unwillingness to provide any basic care and tenderness."
O'Sullivan delivered a fatal blow to Mason's abdomen which ruptured his small intestine five days before his death.
He was handed a nine-year jail sentence in Brisbane Supreme Court last year with a parole eligibility date of July 29, 2022.
Lee was also jailed for nine years but could walk free on parole next month.
On the grounds of manifest inadequacy, Ms D'Ath wants O'Sullivan's sentence increased to 10-12 years and for him to be declared a serious violent offender, meaning he would serve at least 80 per cent.
"This is a man who not only inflicted the blow or blows on a 22-month-old that resulted in the fatal injuries, but he then delayed in obtaining any medical attention when it was obvious to both relative strangers and complete strangers the child was unwell," Mr Byrne said.
"Importantly, these injuries were survivable had they been treated.
"It was a particularly serious example of manslaughter.
Ms D'Ath is calling for Lee's parole eligibility date to be pushed back or for her to serve her entire sentence.
Mason died in O'Sullivan's unit after displaying signs of illness which would have been obvious, including pain, fever, vomiting, lethargy and paleness.
Lee left him there after storming off after a fight in which O'Sullivan, an ice user, threatened violence.
When paramedics were called in the early hours of the morning, Mason had been dead for hours.
Lee was the one person who could have protected Mason but she failed, Mr Byrne said.
Ms D'Ath lodged appeals against both sentences following legal advice from the Director of Public Prosecutions.
A full-day hearing in the Court of Appeal against O'Sullivan and Lee's sentences is taking place in Brisbane on Friday.
Australian Associated Press