Mary Erskine, 55, said her West Highland terrier, Jack, ran out onto the street and was struck by a passing van after the SNP party worker left her front gate wide open.
As a result of the incident at her home in Prestonpans, East Lothian, little Jack had to have his leg amputated.
Mrs Erskine, an Edinburgh taxi driver, said: “Nicola Sturgeon is always saying ‘we have a duty of care’.
“Where is the duty of care in this?”
Mrs Erskine, of Drumtnore Drive, said the SNP canvasser had acted heartlessly after the accident.
She said the man knocked on her door to say Jack and her older Westie, Bobby, had escaped through the open gate, but by the time she was able to get to them the accident had happened.
She said that despite the gate having a sign on it warning of dogs, he told her he didn’t realise they might be in the garden.
She hit out: “He showed no concern as he told me they had got out or after Jack was struck by the van. He simply walked away.
“A neighbour further down the street said when he passed her and she asked if the dog was OK he just said, ‘It’ll live.’
“I couldn’t believe his lack of concern.”
Jack was taken to a local vet but his back leg was too badly damaged to save.
He underwent surgery last Friday to have it amputated and is now recovering.
The total bill for the operation is estimated to be between £3,000 and £4,000.
Mrs Erskine said: “I have insurance, but will still have to pay about 10 per cent of the bill plus the excess, but it is not about the money.
“It is about someone being sent out on behalf of the SNP to leaflet for them without the basic understanding of how to treat people’s homes.
“If a gate is closed when you arrive it should be closed by you when you enter and leave. What if young children were playing in the garden, and had wandered out?
“It is not acceptable.
“I am furious about this, the SNP certainly won’t be getting my vote.”
George Kerevan, Westminster candidate for the SNP in East Lothian, told a local paper he had been deeply upset to hear about the incident.
He said: “As someone who has always had pets, I am distraught at the accident involving Mrs Erskine’s dog and apologise to her for the pain and bother she has suffered as a result.
“I’ve spoken to her on a number of occasions since the incident and am gratified that her dog is now back home and recovering from surgery.
“I have reinforced with all our campaign volunteers the need to be vigilant and respect people’s property as if it were their own, including closing gates properly.
“I shall be keeping in touch with Mrs Erskine and will do anything I can to aid the dog’s recovery.”
The incident occurred on Wednesday last week.
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