The Queensland government is appealing the nine-year jail sentence handed down to the man who killed Caboolture toddler Mason Jet Lee in 2016.

Attorney-General Yvette D'Ath says she has lodged an appeal against the manslaughter sentence given to William Andrew O'Sullivan on August 30.

Mason Lee was found dead at a Caboolture home.

"After receiving legal advice from the Office of the Director of Public Prosecutions, the appeal has been lodged today," Ms D'Ath tweeted on Thursday.

"As the appeal is now before the courts, I will do nothing that might prejudice these court proceedings and will be making no further comment."