Introducing an LNP private member's bill with tougher penalties for people who kill children, Mr Janetzki listed a litany of devastatingly tragic cases.

A 19-day-old baby shaken violently. The baby remained alive for 10 months, crying as if in constant pain and eventually dying. The offender had a previous conviction for assault but was sentenced to only six years in jail for manslaughter.

An infant subjected to repeated violence over a period of time in which the offender contrived occasions to be alone with the child. The infant died due to substantial physical abuse. The offender was sentenced to seven years for manslaughter.

A four-year-old was punched in the stomach by his mother and died of abdominal injuries. His mother was sentenced to nine years for manslaughter but eligible for parole after serving four.

An offender who inflicted abuse on his one-month-old baby girl who suffered fractures to her skull, ribs and legs, an underlying brain injury and injuries to her liver and pancreas. Sentenced to nine years for manslaughter.

A three-year-old punched by her father died a slow, painful death. The offender was sentenced to nine years for manslaughter.

An offender punched his 10-week-old son's stomach while he was in his rocker swing. The father was sentenced to nine years for manslaughter but eligible for parole after five.

Hemi Goodwin-Burke, 18 months old, who was beaten and killed by his babysitter. The offender was sentenced to 8.5 years for manslaughter with parole eligibility after four years.

Mason Jet Lee, 22 months old, after whom the LNP's bill was named, who was found riddled with broken bones, ruptured organs and bruises. He was covered in vomit and blood had pooled around his neck. The offender was sentenced to nine years for manslaughter with parole eligibility after six years.

Mr Janetzki said the system was failing Queensland's children and the families of the victims.

"I am still in disbelief when I think that these offenders, who committed the most sickening of crimes, have all been sentenced to less than 10 years," he said.

A report published last year revealed offenders sentenced for adult manslaughter received longer average sentences (8.5 years) than offenders sentenced for child manslaughter (6.8 years).

The LNP's bill increases the minimum non-parole period for murdering a child from 20 years to 25 years.

It would also create a new child homicide offence.

Under the offence, a person who vigorously shakes, punches, kicks, stamps, throws, squeezes, suffocates, strangles or engages in any violent act that causes a child's death, will be guilty of child homicide and face a minimum mandatory sentence of 15 years in jail.

A person who sexually assaulted a child which led to the child's death, or failed to provide the necessities of life, would also serve a minimum of 15 years.

However, Mr Janetzki said people involved in an accidental death would not be caught by the new child homicide offence, including accidentally running over a baby or an accidental drowning.

"This bill is deliberately targeted towards those who act violently towards a child or who neglect a child they have a duty to care for," he said.

Mr Janetzki said the killing of a child was a shameful crime.

"Any parent or carer who has held a child in their arms knows the vulnerability, the reliance, the trust that child has for you," he said.

"No child deserves to be held in the arms of evil. But all too often, these arms are robbing innocent children of their lives."

The parents and grandmother of Hemi and Act for Mason advocates were in the public gallery as the bill was introduced.

It comes after Labor this week introduced its own bill to toughen penalties for people who killed children, while Attorney-General Yvette D'Ath criticised mandatory sentences.