The death toll from an avalanche in central Italy has climbed to 12, with 17 people still missing at a mountain resort buried by tons of snow and rubble.

Firefighters located five more bodies overnight and the search was continuing on Tuesday in the hope someone might still be alive six days after the disaster.

Rescue crews were buoyed by the discovery on Monday of three of the Hotel Rigopiano's resident puppies, though they stressed the white sheepdogs were found in a boiler room far from where the missing are thought to be.

The first funerals will be held on Tuesday.

Prosecutors are investigating whether a series of missed communications, underestimations of risks and delays in responding to days of heavy snowfall contributed to the toll from the January 18 avalanche.