The bodies, including four members of a single family, were found yesterday at the hot springs in the northern Andean province of Imbabura, the officials said.
"It's an accidental death resulting from the inhalation of toxic gases emanating from the thermal waters," the interior ministry said in a statement.
Local firefighter Carlos Lopez told AFP that toxicological tests had not yet been performed, "but it is confirmed that it is from inhalation of gases."
Members of the community indicated that the victims were taking part in a ritual led by two shamans, both of whom also died, according to Lopez.
At the site, authorities found homemade cane liquor, candles, eggs, medicinal plants, entrails and dead birds, as well as the business card of a shaman offering to solve problems with money, love, work, business and travel.