Disaster authorities are only now reaching isolated parts of the affected provinces of Guadalcanal, Malaita and Makira and Ulawa.
The girl died when a building collapsed on top of her on Guadalcanal after the 7.8 magnitude quake which struck on Friday.
An aftershock measuring 6.9 struck the next day.
The director of the National Disaster Management Office, Loti Yates, said authorities were working with donor partners and international NGOs on the initial emergency response.
