A production date of April 7 this year and a best-before date of April 7 next year were shown on the packaging.
Brain returned the butter to New World Hastings today and received a replacement, she said.
Foodstuffs, which owns Pams, said it takes “food safety very seriously”.
It has strict processes and protocols in place to ensure it maintains the highest standards, a spokeswoman told the Herald.
“If something is spotted, or if a shopper has a concern, we encourage customers to alert a member of the team straight away, so it can be properly investigated.”
Vincent Arbuckle, deputy director-general of New Zealand Food Safety, an authority within the Ministry of Primary Industries, said it has received complaints regarding mould on Pams brand butter.
“While there is no evidence this mould is a food safety concern, our advice to people who see unintended mould in any product, such as this, is to avoid eating it and contact the manufacturer or retailer.”
Arbuckle said New Zealand Food Safety is working with Foodstuffs Own Brands to “establish how the issue arose to prevent it from recurring”.
“Foodstuffs Own Brands is taking action to remove potentially affected products from shelves,” said Arbuckle.
Earlier this month, Foodstuffs said it identified “some quality issues with a few batches of Pams butter”.
It was in response to a report of a shopper purchasing butter with mould on it at a New World in Auckland’s Whangaparāoa.
A spokesman for Foodstuffs said it and Pams would be withdrawing the affected batches while it looks into the matter because “we only want to provide the highest quality butter”.
“We want to reassure customers it’s a quality issue and not a food safety issue.”