The four girls, aged between five and 13, were allegedly left alone in the house, the SABC reported on Sunday.
Police spokesman Sergeant Mmako Mophiring told the broadcaster the cause of the fire could have been a burning candle. The children’s mother was said to have rushed to the house to try to save the girls and was injured in the process.
She was admitted to the Dihlabeng regional hospital, the SABC reported.
Police have opened an inquest docket, and investigations continue.