New Zealand Post says between 1500 and 2000 jobs will go as part of its strategy to maintain a viable business.
The state-owned enterprise outlined its plan at a news conference in Wellington on Friday. It says the majority of jobs affected will be postal delivery staff, following an announcement last week that delivery days will be reduced in mid-2015.
Urban deliveries for standard mail will be able to be reduced from six days to three days a week if necessary, but deliveries will stay at five days a week for rural areas - a cut of one day for some areas.
Other positions to be cut include workers in the corporate, processing and retail areas. New Zealand Post plans to slash the number of post shops it owns from 139 to 50. Some services will be integrated into kiosks or other outlets such as supermarkets.
New Zealand Post chairperson Sir Michael Cullen says jobs will be cut over the next three years and could begin as early as 2014.
"We can't give you precise numbers today, we can't tell exactly who and when and where. And one of the most important reasons for that is we have to engage in consultation with our staff, with their representatives - the two main unions the PWA and the EPMU."
Sir Michael told Radio New Zealand's Checkpoint programme it will be one of the largest reductions in the history of the postal service since the 1980s. He says the core postal system is actually negatively valued at minus $300 million and will increase year by year unless changes are made.
Sir Michael says some positions will go through natural attrition and the company will help those losing their jobs to find other work.
New Zealand Post currently employs 10,500 staff, including Auckland postie Allan Peeperkorn who says he's unsure of what will happen next.
"Well, I'm just going to hang in there and just see what eventuates because, at the end of the day, the employment situation's not great out there.
"We're in Auckland so we've probably got more chance, but in the regional areas ... I feel really sorry for people ... There's not much opportunity, they're just basically going to be joining the dole queue."
Listen to Checkpoint interview with Sir Michael Cullen
NZ Post being primed for privatisation - union
A union associated with New Zealand Post says workers are shocked at the extent of the job losses.
The Engineering, Printing and Manufacturing Union says the dramatic cuts are attacking core services and have the hallmarks of another state-owned enterprise being slimmed down and primed for privatisation.
Joe Gallagher, senior spokesperson for postal services at the EPMU, told Checkpoint the union fears for its members in the regions, particularly.
"It's a really hard job climate - particularly in those regions that seem to be hit constantly by job closures - and the Government doesn't seem to have any regional stimulus concept to support these regions, create these new jobs. I just don't know where these people are going to find new jobs."
Mr Gallagher says the issue will not be dealt with by the natural attrition of about 1000 workers a year that New Zealand Post chairperson Sir Michael Cullen predicts.
Mr Gallagher says the Government signalled last week what levers it would use to reduce postal services, and Friday's announcement shows how hard it will pull them.
The Labour Party says the Government needs to come up with an employment strategy.
Listen to Checkpoint interview with Joe Gallagher