The LNP's new laws are needed now more than ever after the Palaszczuk Labor Government proved incapable of being tough on child killers.
LNP Leader Deb Frecklington said minimum mandatory sentences were not part of the Palaszczuk Labor Government's proposed new laws.
"The Palaszczuk Labor Government had an opportunity here to make significant changes in our justice system to protect Queensland kids, but their response was weak," Ms Frecklington said.
"The changes Labor have put forward merely tinker at the edges and they are not tough enough.
"They fall well short of what's required to deliver punishments to child killers that meet community expectations.
"I am determined to protect our kids and we'll punish the monsters that harm them.
"Judges are passing too many soft sentences for child killers – so I'm calling for minimum mandatory sentences instead.
"The LNP's Mason Jett Lee Laws would introduce a minimum non-parole period of 25 years for the murder of a child and we would introduce a new offence of child manslaughter with a mandatory minimum sentence of 15 years.
"Enough is enough. There must be no more soft sentences.
"We will introduce our laws in Parliament and if Labor votes them down, I'll take it to the people of Queensland at the 2020 election."
LNP Shadow Attorney-General David Janetzki said the LNP was determined to bring penalties into line with community expectations after the killer of toddler Mason Jett Lee was jailed for nine years - with a non-parole period of just six years.
"There is no worse crime than killing a child," Mr Janetzki said.
"The LNP's Mason Jett Lee Laws will more than double the current penalties being handed out.
"We need to send a message that people who murder a child will be severely punished. It is what the community expects.
"We've seen time and time again that when it comes to community safety issues, you just can't trust Labor."