Austrian prosecutors dropped all charges Friday against a ski companion of Dutch Prince Friso, who was caught with him in an avalanche in February that left the royal brain-damaged and in a coma.

The unnamed old friend, identified by media as the director of the Austrian hotel where the Dutch royal family stays every year, escaped unscathed but had been charged with causing injury through negligence.

"Both skiers were aware that skiing off-piste in deep snow always carries the risk of starting an avalanche," Heinz Rusch, spokesman for the prosecution in the western Austrian town of Feldkirch, said Friday.

The two men thus shared responsibility, he noted, adding there was no cause for criminal prosecution in this case.

On February 17, Prinz Friso and his unnamed companion were caught in an avalanche while skiing off-piste in the ritzy western Austrian resort of Lech.

At the time the avalanche alert level was at the second highest, posing a particular risk away from the prepared ski slopes.

The prince, an experienced skier but who unlike his friend did not have an avalanche airbag, was hospitalised in critical condition after spending some 20 minutes under the snow and suffering a lengthy heart attack.

Austrian doctors later said the prince, Queen Beatrix's second son, may never again regain consciousness. He was later transferred to a London hospital for long-term care.