The blaze, which occurred shortly after midnight on Thursday, is thought to have been caused by sparkler candles on champagne bottles igniting the ceiling, leading to a rapid 'flashover' incident.
Victims, many of whom are young and from various European nationalities, are proving difficult to identify due to the severe nature of their burns.
Many of the injured are being transferred to specialist burns hospitals across Europe as local medical facilities reached capacity.
Swiss authorities have launched a criminal investigation into the incident, ruling out an attack and focusing on potential issues with renovation work, materials, licensing, and safety arrangements.