A 22-year-old man has been arrested and is in hospital under police guard after he allegedly stabbed his 43-year-old mother and his three siblings. 

Police spokesperson Capt Mavela Masondo said the man killed his mother and four-year-old sister and severely injured his other two siblings aged nine and 16 before stabbing himself. 

Masondo said the mother and the four-year-old girl were certified dead on the scene while the nine-year-old girl and 16-year-old boy were taken to hospital in a critical condition.

"It is alleged that the suspect had an argument with his mother at about 1am after he demanded money from her," said Masondo. 

Masondo said the suspect allegedly took a kitchen knife and stabbed his mother several times.  "The suspect continued to stab his two sisters and a brother before turning the knife on himself." 

Police have opened two cases of murder and two cases of attempted murder for further investigation. The suspect will appear at Sebokeng magistrate's court as soon as he is out of hospital.