A four-year-old child is being treated for extreme trauma after being held hostage at knifepoint on a rooftop for almost 24 hours by her father, Mpumalanga police said on Monday.

Superintendent Malcolm Mokomene said her father held a knife to her throat on Sunday morning as he dragged her on to the roof of their house in Calcutta, near Bushbuckridge at about 7am.

Her mother, grandmother and other relatives were present and called the police for help.

About 50 policemen and hostage negotiators tried to convince him to leave the girl, but he refused, said Mokomene.

Unusually, he was not making any demands and it emerged during the negotiations that he was using her as a "human shield", claiming someone wanted to attack him.

"That convinced us that he has a mental disorder," said Mokomene.

The afternoon and evening passed with him still pressing the knife against the child's throat, as police tried to convince him to hand her to them.

A special task team was also on standby.

Eventually at about 4.30am on Monday, police made a breakthrough and the man passed the small girl down to them.

"She is severely traumatised," said Mokomene.

She had to be treated in hospital for shock and for exposure.

The man has been arrested and will face charges of attempted murder and child neglect.

Sapa