The owner of the dogs, described as a man of European descent in his 50s or 60s, with a slim build and a beard, was wearing a hi-vis vest. The dogs came back for a "second go" but the owner called them off.
She informed the man his dogs had bitten her but he left as a Kakanui woman came to her aid, Mr Sheffield said.
"If they got her to the ground I hate to think what would have happened," he said.
While Mrs Sheffield was grateful for the help she received from the woman, she wanted the dogs' owner to accept responsibility.
Kakanui residents spoken to after the attack had not recognised the man.
A Waitaki District Council officer came and took photographs of her injuries, but a council spokeswoman declined to provide the ODT with the photos.
Council enforcement officer Tristan Hope said under the Dog Control Act 1996 and the council's dog control bylaw, dogs must be "kept under effective control whether or not they are being exercised in a lead-only area".
However, the beach was not controlled or managed by the council and dogs were allowed off-leash on the beach at Campbells Bay.
Information can be provided by calling the Waitaki District Council (03) 433-0300 or by emailing animal.control@waitaki.govt.nz.