The victims were identified as 41-year-old Muna Elmufatish; daughters Hanin, 14, Basma, 13, and Amal, 9; and sons Mustafa, 5, and Yehya, 2, Sky News reported.
Two others, believed to be the 51-year-old father and his 16-year-old daughter, escaped the blaze with burns to their bodies. The girl was in critical condition while the man was stable, police said, according to media reports.
Neighbors told Sky News they awoke to the sound of several explosions before the fire, which gutted the semi-detached house.
"First there was an explosion three or four times and then after this we came out and saw the fire," Gito Parma told Sky News.
Six fire engines and 30 firefighters attempted to tackle the blaze, The Telegraph reported.
The cause was under investigation. The blaze was not believed to be of suspicious origin, a police spokesman said.