"Householders standing on their own doorsteps may also have their conversations with their posties being recorded without their knowledge," Maynard alleged.
"NZ Post had told the Postal Workers Union that the camera would be used to record visual images for use in investigating accidents and incidents threatening the security of its employees.
"The union learned only last week that the cameras also record sound, and that NZ Post management has been downloading and secretly eavesdropping on the private conversations recorded without the knowledge of the employees."
Maynard said NZ Post had refused the union's written request asking the company to stop all audio recordings until the privacy issues could be resolved with the guidance of the Privacy Commission.
NZ Post fitted its Paxsters with forward-facing high-resolution dashboard type cameras which had a GPS function allowing the company to pinpoint the exact location and addresses of all images and conversations they recorded, Maynard said.
The cameras and audio automatically recorded at all times the Paxster vehicles had their ignition switched on, he alleged.
"NZ Post had demonstrated to the Union the forward-facing type camera mounted in each Paxster to record incidents or accidents. However the company made no mention of audio recordings. Despite the Union now making strong objections to NZ Post, the company insists on continuing to make audio recordings of both its employees and members of the public.
"The PWUA has no issue with NZ Post using recording technology to safeguard the safety and security of postal workers, but believes that NZ Post's current practice goes well beyond security and breaches the privacy rights of its employees and members of the public."
Maynard said the union found out about the recordings last week from a postie, who "became aware a number of her conversations had been recorded and then listened to".
He had been in conversation with the Privacy Commissioner, who said it could deal with the individual complaint of the postie.
"There's three issues, number one is a postie being audio recorded without her knowledge, number two is that most posties were never aware of the recordings, and number three is the public, they didn't know they were being recorded... But the commissioner can only deal with the individual complaint."
Maynard said NZ Post had made no effort to make it clear to all posties their cameras also recorded audio.
He said he'd been in discussions with NZ Post's general manager, Matthew Riordan.
"He said it was 'industry standard'."
A New Zealand Post spokeswoman said the company took the "safety and privacy of our staff and members of the public very seriously".
"We have been in contact with the PWUA on this issue and are in further discussions with them. We are also in discussions with the Privacy Commissioner."
The Paxster recording devices are there for health and safety reasons, she said, to help the company understand what has happened in the case of an incident.
"Whilst we work with PWUA and the Privacy Commissioner, all team leaders must seek the permission of the Acting General Manager of Operations before accessing any Paxster camera recordings for any purpose."
The recordings were wiped from the Paxsters after 1-2 days, and copies are not kept, she said.
The case follows that of National MP Todd Barclay, who announced last month he was stepping down as an MP following a political scandal involving allegations he had secretly recorded an electorate office staff member.
Police have reopened an investigation into Barclay following claims that he left a dictaphone running in his Clutha Southland office during an employment dispute.
It is illegal to intentionally intercept by means of an interception device private communications you are not party to.
