According to a press release from New Zealand's Ministry for Primary Industries, the Canadian woman only declared her dirty boots to biosecurity officials.
After security at Auckland Airport insisted her baggage had to be checked as well, she reluctantly revealed that she had an extra passenger with her.
"She was very reluctant to have the handbag x-rayed, saying it had already been checked by our quarantine officers. She only revealed the cat after we insisted the bag will have to undergo further biosecurity checks," ministry official Craig Hughes said.
The Canadian woman had kept her cat Bella in her handbag throughout the long flight from Vancouver. A ministry spokesperson told BuzzFeed News the cat arrived "in a very subdued state, but we don’t know whether it had been sedated or not."
"It is very rare for our biosecurity staff to intercept domestic pets from arriving international air passengers," the spokesperson added. "The last time it happened was about five years ago. This incident involved a dog."
As punishment, the woman was forced to take the next flight back home to Canada, along with Bella.
New Zealand called it a "very stupid attempt at smuggling."