Savage Geraldton robbery of 79-year-old caught on CCTV

Horrific footage of a 79-year-old woman being knocked to the ground in a street robbery in Western Australia has emerged.

The callous attack happened at about 9am this morning in Hutchinson Street in Geraldton, about 420km north of Perth.

The footage, captured from a nearby home's CCTV, shows the elderly woman approached from behind by her attacker who then tries to steal her handbag.

But she holds onto it - so he drags her along the bitumen like a rag doll, and she eventually loses her grip and he runs away with her purse.

Janina Sykes, whose camera caught the incident, rushed to the woman's aid when she heard her screams.

"It looked like he was punching her, so I said 'let her go, let her go' and I came out of the door and he ran away," Ms Sykes told 9NEWS.

Remarkably the woman received only grazes during the struggle, and was disappointed she could not take a chunk out of her attacker.

"She was upset that she couldn't get a bite in," Ms Sykes said.

"She really wanted to bite him."

Anyone with information should contact Crime Stoppers on 1800 333 000 or Geraldton detectives on (08) 9923 4555.