A 16-year-old girl is fighting for her life in hospital after being attacked by her friend's dog in the NSW Hunter Valley region.

Emergency services were called to the girl's friend's home on Broughton Street in Singleton, north-west of Newcastle, about 11.30am today.

The girl was attacked by the dog, described as a 10-year-old large mixed-breed, before passersby managed to pull it off her.

She had suffered critical head, neck and body injuries and was flown to John Hunter Hospital.

Police and council rangers were at the scene to euthanise the dog, with consent from the owner. 

The dog's breed was not disclosed. 

Investigations are continuing.

DOWNLOAD THE 9NEWS APP : Stay across all the latest in breaking news, sport, politics and the weather via our news app and get no

See Full Page