Cuts to urban postal deliveries around the country will be the "nail in our coffin", organisation for the elderly Grey Power says.
However, the Wairarapa Chamber of Commerce says local businesses will not be affected by the changes.
Urban delivery will be slashed, from six days a week to at least three, and most PostShops could be replaced with self-service kiosks, from June 2015, as NZ Post reacts to a decline in mail volume. Rural deliveries will not be affected.
Dannevirke Grey Power treasurer Lorris Haste said the changes were a "disgrace".
"A lot of elderly people depend on it [the mail], even if it's just a letter from an old friend or something. Lots of times that would be all they had in their day. It's just another nail in our coffin," Mrs Haste said.
Mrs Haste said Grey Power members would share her opinion. "I daresay Grey Power will rise to this and lobby the Government on it.
I can see that will happen. It's just so stupid."
Mrs Haste said she relied on the post and as Grey Power member secretary, as well as treasurer, received mail most days. "There are lots of times that we need the mail because we've got a deadline on something. We get mail six times a week at the moment. It's a big difference."
She also questioned what would happen to NZ Post staff that could be out of work as a result of the cutbacks. "What's going to happen to them? It's just another thousand that will be put on the dole. I don't think they have thought it through."
Wairarapa Chamber of Commerce chief executive Stephanie Gundersen-Reid said the changes would not have "too much effect" on local businesses.
"A lot of stuff is done online now in business. Mail is great and it's unfortunate that people will be made redundant. However, business is very much done online."
The Wairarapa Chamber of Commerce has more than 220 members.
More than 1000 posties and retail staff could lose their jobs after the Government gave NZ Post the go-ahead to move to three-day-a-week deliveries but spokesman John Tulloch said he could not say how that would affect job losses for staff in specific areas, such as Wairarapa.
Communications Minister Amy Adams said postal volumes were declining in New Zealand, at a rate of about 8 per cent a year, and without changes NZ Post would need millions in subsidies each year.
"It is clear that if changes are not made ... then significant and ongoing government subsidisation in excess of $30million a year may be required." However successful lobbying has seen rural deliveries maintained.
"Through negotiations, I have secured agreement from New Zealand Post that it will limit any introduction of a minimum three-day delivery to only urban areas, maintaining five-day delivery in rural delivery areas."
Changes to the agreement will also allow NZ Post to operate from self-service kiosks as well as physical postal outlets.
NZ Post is required to maintain a retail network of at least 880 points of presence.
Of the 880 NZ Post have agreed to maintain 240 outlets where customers can receive personal assistance from an employee or agent of NZ Post.