Dutch Prince Johan Friso, who was buried in an avalanche a week ago while skiing in Austria, has suffered severe brain damage and may not come out of a coma, his doctor told a press conference on Friday.

Queen Beatrix's middle son, who gave up his right to the throne a decade ago, was skiing off-piste near Lech in the Austrian Alps, when he was caught in an avalanche. He was trapped under the snow for 25 minutes before he was pulled out unconscious, and has been in critical condition ever since.

Because the prince was stuck under the snow for a very long time, he did not get enough oxygen, his doctor, Wolfgang Koller, told a press conference.

The lack of oxygen led to a cardiac arrest, which lasted for 50 minutes. During this entire period the patient had to be resuscitated. This is an exceptionally long period, you can say too long a period, Koller said.

Koller said if the 43-year-old, hospitalised in Innsbruck near Lech since February 17, wakes from the coma his rehabilitation will take months, possibly years.

(Reporting by Tjibbe Hoekstra; Editing by Sara Webb)