Dog almost severs woman's arm

A 67-year-old woman has had her arm nearly torn off by a dog she was looking after for her family in Victoria's far southwest.

The woman has suffered gruesome injuries to both arms and will need surgery at the trauma centre in Melbourne's Alfred Hospital.

"She had just come in from outside, walked back into the house and the dog was in the house," ambulance Victoria Paramedic Justin Nunan told AAP.

"It just attacked her unprovoked."

The woman's neighbour in the town of Portland heard her screams and ran over to help, Mr Nunan said.

"The neighbour actually came straight in and beat the dog away with a bin. That's probably saved her life."

She was airlifted to Melbourne with her right arm almost severed, a part-severed left arm and injuries to her face.

The woman's family is currently driving from Portland, about 400km from Melbourne.

The Staffordshire pitbull cross was put down after paramedics called police for their own safety, a police spokeswoman told AAP.

- AAP