Four family members, including two children, died in a fire at their home in Kalkfontein, Kuils River, on Tuesday, authorities said.
A man, woman and two girls were trapped in their home when the City of Cape Town's Fire and Rescue Service arrived, spokesperson Jermaine Carelse said.
Carelse said despite their efforts to contain the blaze to a single structure, the man, woman and their two daughters could not be saved.
The blaze started after 03:00 on Tuesday and was extinguished at 03:55. The cause of the fire is unknown and police were continuing with their investigations.
Western Cape police confirmed death inquest dockets had been opened.
"Death inquest case dockets have been registered after four people - two adults, aged 25 and 39, and two girls, aged 1 and 9 - lost their lives in a fire at their residence in Elizabeth Street, Kalkfontein, Kuilsrivier, between 03:00 and 04:00 this morning," police spokesperson Captain FC van Wyk said.
Anyone with information about the incident can contact the Kuils River police on 021 900 2800 or Crime Stop on 08600 10111.