The latest victim was a nursing graduate, the 10th fatality among a group who checked into the Bed and Breakfast hotel in Tuguegarao city ahead of professional licensing exams, said city police chief Superintendent Pedro Martirez.
The six others who died included a family who owned a motorcycle parts store beside the hotel, which firemen suspect was the origin of the blaze.
Eleven other people were injured, while 19 guests and staff were rescued unharmed.
Justice and interior ministry investigators would look into the cause of the fire and recommend possible prosecutions as well as remedial measures, Martirez said in a report.
The deputy fire marshal for the region, Senior Superintendent Sergio Soriano, said the blaze could have started at a storeroom at the shop that contained flammable materials.
“It may have stemmed from an electrical short circuit, with the sparks hitting containers of gasoline,” Soriano told DZBB radio in a telephone interview from Tuguegarao.