"There was no room for negotiating at all. My bag went through x-ray and I was shocked myself, I just completely forgot."
Hill said the Ministry for Primary Industries staff were "pleasant", but left no room for negotiation.
"They were quite pleasant, they certainly weren't unpleasant. But there was just no leniency at all."
As a dual Australian/New Zealand citizen living on the pension, the $400 fine represented a full week's pension payment, she said.
When filling in a biosecurity declaration form before arrival, the nectarines were the last thing on her 86-year-old mind, she said.
Speaking from Sydney, Hill's son, John Hill, said the level of fine imposed on his pensioner mother was "outrageous".
"This is an unfair piece of Draconian legislation that must be raising a huge amount of revenue for the Ministry of Primary Industries (MPI).
"It's a full week's pension payment for my mother, cash that she won't have available to spend in New Zealand to the benefit of the tourist industry or the local economy."
Biosecurity New Zealand spokesman Steve Gilbert said that New Zealand had strict biosecurity rules to stop unwanted pests and diseases from entering the country.
"We take a tough stance on travellers that put New Zealand at risk, even if their actions are not deliberate.
"We issue infringement notices when we believe a passenger has unintentionally failed to declare a risk item [in this case, fresh fruit].
"If we believed the passenger had intentionally tried to smuggle the fruit into New Zealand, she could have faced prosecution."
The fresh nectarines could easily have been carrying fruit fly, which was a major pest in countries such as Australia, Gilbert said.
"We appreciate that some of the most dangerous goods we seize from travellers seem harmless to some.
"In reality, many could devastate our economy and environment."
