Vanessa Wheeler thought Senna had been bitten when she discovered her unable to walk properly and with congealed blood on her upper left leg last month.
She took the cat to a vet, who prescribed antibiotics and painkillers - but at another vet clinic four days later an x-ray revealed the true extent of the animal's injury.
"She had a pellet lodged in her shoulder. I said 'you're joking'. Whoever shot her must have been looking straight at her as the bullet has entered her chest front on."
Miss Wheeler was stunned, particularly because 10 years earlier, her family cat had been shot in a similar way and left paralysed.
She was relieved Senna did not suffer any permanent nerve damage and is walking again.
The 34-year-old and her partner Aaron Foss, who live in Glen Innes, complained to the police.
But she was told that without evidence of who shot the cat the case could not proceed.
Miss Wheeler, a marketing manager, was concerned the culprit might still be "taking pot shots" at animals or even children.
The pair went to Paw Justice, a charity aimed at stopping animal abuse. Co-founder Craig Dunn offered a $1000 reward for any information leading to the prosecution of those responsible.
Mr Dunn said: "You don't want these people going round in your neighbourhood - they start with animals and then they're on to the next thing."
Airgun ownership
Anyone aged 18 or older can own and use an airgun.
But you can be arrested and fined or imprisoned if you:
Possess or carry an airgun without a lawful purpose.
Carelessly use an airgun.
Fire an airgun in a way that may endanger, annoy or frighten anyone or damage property.
Point an airgun at someone.
Sell or supply an airgun to an unlicensed person under 18.
- Natalie Akoorie, New Zealand Herald