The blast initially left six people burnt, four in critical condition, with a thousand tourists evacuated, the emergency services said.
The Norwegian woman died at 5am on Thursday, a hospital spokesperson told newspaper Aftenposten.
Three others were also hospitalised while 17 people were treated for panic attacks.
The accident happened in the early evening at the Cordial hotel in Mogan, in the Spanish archipelago off the northwest African coast just as a tanker
truck was delivering gas.
"After the explosion, part of the hotel's spa roof collapsed," the Canaries emergency services said.
The 1,000 evacuated hotel guests were allowed back into the main hotel which was not damaged, said Gema Suarez, spokesman for the local mayor.
Among the six seriously injured, three were women were said to be in critical condition with 70 percent burns, including the spa chief and a cleaner.
Mogan is a tourist town of some 20,000 residents situated in the south-west of Gran Canaria.