The Ministry of Government Relations investigated the fire on the Ahtahkakoop (attack-ah-koop) Cree Nation on Dec. 29 and says it was caused by a wood-burning stove.
Donna Kay, who was 61, and 10-year-old Teegan Ahenakew were unable to get out.
Their remains were found at the site on Dec. 31.
Two men managed to escape before the home was completely engulfed.
The reserve is about 170 kilometres north of Saskatoon.