The victim was a 74-year-old woman named Therese Johanna.
The victim was sleeping in the house and at the time there were three small children and the deceased victim's son and niece in the house.
The son of the deceased victim had seen the fire in the house and had seen that the mother had caught fire.
He had tried to extinguish the fire by using water.
However, the fire had already spread and the woman had been severely injured and they had called the ambulance service.
The victim was pronounced dead on admission.
Marawila Additional District Judge and Magistrate Heshantha de Mel arrived at the arson site and conducted preliminary magisterial inquiries.
The body has been ordered to be sent to the Judicial Medical Officer of the Chilaw General Hospital for an autopsy.