Sandakan Zone Fire and Rescue chief Andre Andrew said Amanda Faizal, eight, and her sister Marsila, four, perished in the 7pm incident.
He said a 20-year-woman, identified as only as Ekin, suffered 70% burns while a man, Hasim Pinando, 32, was injured.
The six-tonne lorry caught fire after skidding into a ravine and the charred bodies of the two sisters were found in it, he said in a statement here today.
He added that the victims’ bodies and the injured were sent to Duchess of Kent Hospital in Sandakan.