The child was dumped in a field in Gabon, on June 27.
Spokesperson Capt Alfred Nakana said it is not clear whether the child was dead or alive when it was dumped.
The dog owner, who lives near the dump, became concerned when he noticed his dogs feeding on something on the dump.
“He went to investigate and saw that they were eating a baby,” said Nakana.
The police were called to the scene and found the dogs had already eaten the child’s upper body.
Nakana said they suspect the child was dumped at night, after its birth.
The police are searching for the mother of the child and have urged anyone with information to come forward.
The Daveyton police can be contacted on 011 845 9800.
Daveyton was also the place where a minibus taxi driver, allegedly at the hands of police, was killed recently in a barbaric act.
“What is happening is worrying…. It is a sign that we are a very angry nation and calls for something to be done,” said ANC heavyweight Gwede Mantashe.
“If you look at what happened in Daveyton, no normal person can do this.”
Mozambican Mido Macia, 27, was found dead in the Daveyton police station cells.
He was allegedly attacked by policemen and dragged behind a police van after being arrested for a traffic violation.
Eight policemen who were arrested in connection with the attack are expected to apply for bail in the Benoni Magistrate’s Court on Friday.
According to the newspaper, Mantashe called Macia’s death a xenophobic killing.
“If you are a foreigner and killed in our country, it is xenophobic,” he was quoted as saying.
“What happened is barbaric…. Whether South African or Mozambican, this is terrible…. It is a human being who died in a most inhumane way.”
Mantashe said this was not a narrow issue.
“You can see it in the cases of police brutality, violence against women and children, and service delivery protests.”
“We need to look at what is the problem we as a society are facing. Are we traumatised?” he asked. – SAPA