The couple had been preparing the strawberries for their two children, aged 3 and 7.
Rayner, a 45-year-old teacher, said he immediately called the Pak'nSave Cameron Rd store where the strawberries were bought, as well as police.
Police confirmed the matter had been reported and said they had referred it to the Ministry for Primary Industries (MPI).
Rayner said the strawberries were in a punnet. The foreign object had a standard pin head and was "completely hidden inside the strawberry".
"She was cutting them into pieces and literally hit the pin.
"What kind of sicko does that?" he said.
"We were just stunned to be honest. It was like 'oh my goodness, we have seen this in the news and now I am looking at it myself'. It was definitely very surprising."
He hoped the store could use CCTV to track down the offender.
"I'm not sure how far back they can trace things, but hopefully they will be able to catch the person and make it so they get enough of a sentence that no one else will try something this stupid."
In future, Rayner said he would grow his own strawberries.
"There's no way in God's green earth we're buying any more strawberries this summer."
Rayner said he immediately called Pak'nSave and was asked to return the fruit to the store.
"I said you need to get into a car now and come around here to pick this up."
He also called police who instructed him not to pass the product back to the supermarket. Instead the contaminated food they would be collected by MPI staff.
The Herald contacted the North Island brand named on the punnet. A spokeswoman was not aware of the find and said she didn't believe it.
She referred questions to Strawberry Growers New Zealand.
"I'm not going to comment. I don't believe it. I just think the media should not report it because that's when you get copycats."
Foodstuffs NZ spokeswoman Antoinette Laird said the company was "aware of an issue with a customer finding a pin/needle in a punnet of strawberries" purchased at its Tauranga Pak'nSave store.
The remaining product has since been removed from the store's shelves.
"We are liaising with the authorities directly regarding this and as such we are unable to comment further.
"Customer safety is our number one priority and we encourage all customers to contact stores directly should they ever encounter a tampering issue with a product."
MPI said it had spoken to the complainant and was working with Pak'nSave to investigate the incident.
The discovery is the latest in a string of disturbing incidents involving needles in fruit.
A needle was found inside a punnet of strawberries purchased at a supermarket in the South Island last month.
Police were investigating the incident and said the fruit was purchased in South Canterbury's Geraldine.
In September three needles were found in three strawberries in one punnet at Countdown St Lukes in Auckland.
An MPI spokeswoman said then they were aware of a report of needles being found in imported Australian Choice brand strawberries at the store.
Customers were advised to return the brand as a precaution, though the brand was not implicated in the Australian strawberry contamination and associated recalls that created shockwaves over the Tasman earlier this year.
Police are also investigating after a needle was found in a capsicum bought at a Countdown store in Tauranga last month.
