She was told by her management, police wouldn't be interested in the particular scam.
Rather than commending her for her actions, she was then threatened with a possible jail sentence for breaching the Postal Services Act.
The postie explained she was honouring the values taught to her by her grandparents by doing "what is right", a value she said New Zealand Post taught to their employees.
Despite the threats from the company about dismissal or a jail sentence, Carolyn would continue to warn the rest home and other residents of the new scam by delivering a notice about scam mail.
Postal Workers Union of Aotearoa district president John Maynard said New Zealand's Post's actions were concerning.
"It seemed they were trying to discipline her for opening other people's mail but that wasn't the case."
He said he assumed New Zealand Post management thought Carolyn had opened the mail to verify it was a scam, which was illegal.
"In fact, she found this out through another postie. She didn't open anyone's mail."
Mr Maynard said Carolyn's actions to protect residents, especially the elderly, was impressive.
"We were really impressed with the postie who felt really strongly about this matter and she didn't want to see people scammed.
"We think it's very important that New Zealand Post posties are more proactive like this," he said.
He said he was shocked by state-owned enterprise threatening Carolyn with a possible jail sentence, instead of commending her on her actions to protect residents.
"They are way out of line on this."
He said New Zealand Post should be doing more to protect residents from being scammed.
"They should have alerted people in the local area to see what was going on."
Mr Maynard said New Zealand Post were still investigating and a meeting was set up for next week.
He said police were currently investigating the scam mails.
A New Zealand Post spokesperson said it didn't have the "power" under legislation to open mail, even if a scam was suspected or detected.
However, if a recipient opened the scam mail and contacted the police, the state-owned enterprise would take action if required.
He said this particular Malaysian Lottery scam has circulated around the country for many years.
Carolyn's managers "made every effort" to warn her of the seriousness of interfering with mail, he said.
"It was accepted and acknowledged that while she knowingly breached her conditions of employment, she thought she was doing the right thing."
He said New Zealand Post worked closely with other agencies including police, NZ customs and Netsafe to monitor scam activity to prevent scam mails from entering the country.
"New Zealand Post has been successful over the last few years in stopping a volume of scam mail coming into the country, but only because customers receiving the mail made complaints with Police and other reporting agencies (Netsafe). Even then we require the the mail to have a local (NZ) return address or local account to take any further action."
