South Africa's law should continue to be harsh and show no mercy toward the perpetrators of child-abusers, a government spokesperson said on Friday.

"As a nation, we must never tolerate any form of abuse against children," said Phumla Williams, acting directer general of the Government Information and Communication System.

She was speaking after the Durban High Court handed down a 20-year jail sentence on Thursday to a Durban mother who brutally murdered her child in 2014, a case that shocked the nation.

The government welcomes the 20-year sentence imposed on the mother, Williams said.

The court found that the mother, who cannot be named for legal reasons, murdered her three-year-old daughter, who had endured being beaten, starved, burnt with cigarettes, had chili powder put in her nappy and tied to a bed at night.

"One cannot imagine the pain that the poor baby suffered at the hands of adults who clearly displayed an inhumane behavior towards this little child. We will not stop speaking about these barbaric acts until we rid our society of such acts," said Williams.

The baby's grandmother, who was also charged with the murder and assault, died of natural causes this year while awaiting trial in prison.

In South Africa, which is among the countries that have the highest crime rate in the world, 800 to 900 children are murdered every year, according to police.

In 2016, the United Nations ranked South Africa as among the world's 10 most violent nations.

The government has put in place child protection mechanisms such as legislation and international instruments that the country has ratified as a commitment to the protection of children's rights. Key among these is Section 28 of the Constitution which specifically deals with and lays the foundation of children's rights.

Williams urged the public to join in the fight against child abuse.

"As a society we must expose these abusers and we must act to prevent abuse of children in our communities," she said.