A Nelson postie was threatened with the prospect of being sent to prison after she refused to deliver letters which she thought were part of a scam, the Postal Workers Union says.
The union says the postie became concerned after a colleague received one of the letters, which claimed the recipient had won a $180,000 prize.
Union representative John Maynard said she was then called to a meeting with management after she refused to deliver about 20 of the letters, some of which were addressed to rest home residents.
Mr Maynard said he had been a witness at the meeting where the postie was threatened with a jail term.
"They came back to her and said we're not giving you a warning this time, next time we won't be so lenient, and then they read to her section 20 of the Postal Services Act, which includes a penalty of up to six months' imprisonment."
Mr Maynard said the postie took that as a direct threat.
He said posties were required to deliver deliverable mail, but the postie had very strong principles about her job and did not want to be party to a scam.
She had reported the scam to her superiors and was repeatedly told to deliver the letters, Mr Maynard said.
Now the postie is pushing for the legislation to be changed so posties are actually encouraged to protect against scammers.
Mr Maynard said the police told the union they would have expected NZ Post to alert the Nelson residents about the scam.
"We only subsequently discovered New Zealand Post has a policy of working with Police, working with Customs - they never told us that, they just told me 'you get her back on delivery or she's in serious trouble."
In a statement, New Zealand Post spokesman Richard Trow said it was ridiculous to claim the postie had been threatened with jail.
He said the company accepted the postie thought she was doing the right thing.