Oscar Pistorius should be convicted of murder and not culpable homicide, prosecutors will say as an appeal against his conviction was launched.
The National Prosecuting Authority (NPA) will appeal against Pistorius' conviction for culpable homicide and his five-year prison sentence.
The 27-year-old was jailed last week for killing his girlfriend Reeva Steenkamp in a volley of gunshots, but he could be free in just 10 months.
NPA spokesman Nathi Mncube confirmed the appeal on Twitter.
Pistorius was not convicted of murder by judge Thokozile Masipa, who said the facts were not available to show he intended Steenkamp to die.
Instead, Pistorius was convicted of negligently killing her in a fatally flawed and grossly disproportionate bid to protect the model and law graduate.
Pistorius' uncle Arnold last week said the family accepted the sentence passed upon the fallen track icon and so would not appeal.
But a significant portion of public opinion has condemned it as too soft on Pistorius.