Matthew Scown was convicted of manslaughter, after not providing him the medical attention he needed, and on Wednesday, he was sentenced to four years' jail for his crime.
She said offenders are "laughing" after a series of cases in which child killers have had charges reduced, including a man who tortured his infant daughter to death.
Tyrell Cobb's mum Heidi Strbak also faces charges over his death in 2009.
"There's not a day goes by that he (Scown) doesn't think of Tyrell", Mr Allen said.
'Absolutely unacceptable and I think everybody is feeling it today'.
'The public was rightly disturbed by the response of Mr Matthew Scown as he left court yesterday after sentencing, ' she told Parliament.
However there's been universal outrage over the case, with children's safety advocates calling for him to be put behind bars.
"Rather the Palaszczuk government has recognised an ongoing concern in the community that needs to be explored", she said.
"When the death of a child occurs, we are all heartbroken, but when these deaths occur at the hands of another person, we all want to ensure that the community's expectations are being met in the justice system".
In sentencing Justice Martin Burns said Tyrell would have been "in extreme pain" and "very, very ill".
Four-year-old Tyrell Cobb died on the Gold Coast in May 2009, after suffering stomach injuries and internal bleeding that had been caused by blunt-force trauma.
'You ought to have acted, ' Justice Burns said.
Scown tried resuscitating the child but when paramedics arrived they found Tyrell cold, clammy, non-responsive and without a heartbeat. "So if you know it's happening and you haven't done anything to stop it, you're as guilty as the perpetrator", Hetty Johnson from Bravehearts said. He called Triple 0 only after Tyrell had begun vomiting bile.
"You contacted Tyrell's father to persuade Tyrell's mother to get Tyrell medical treatment", Justice Burns told Scown.
He had initially been charged with murder but pleaded guilty to lesser charge ahead of sentencing.
Mr McCarthy said the mother, instead, went with her brother to get cigarettes, leaving Scown to care for Tyrell.
'Your failure to obtain medical assistance for him renders you criminally negligent for his death'.
"The horror of all of this is that the injuries Tyrell sustained were treatable and that he would have survived if he received treatment when he first became symptomatic", Justice Burns told the one-time Gladstone-based worker.
The court also heard Scown offered "considerable co-operation", and had already spent 987 days in prison.