Affected New Zealand Post workers in Northland may be redeployed to other areas once the FastPost service stops operating from January.
NZ Post this week announced FastPost service would no longer be available following a review of the company's priority mail network.
The change will force people to use courier products as an alternative way of sending priority mail.
Currently only 1 per cent of all mail throughout the country is sent using FastPost and during the last year the number of items sent has declined by 23 per cent.
"The amount of all letter volumes continues to decline significantly, at a rate of approximately 60 million items a year and despite ongoing cost reductions, this change is necessary," NZ Post said.
Standard Post remains unaffected.
NZ Post spokeswoman Amanda Broatch said the company would only be able to confirm ongoing jobs for its Northland-based FastPost employees once changes were worked through.
However, she said new opportunities would be explored with affected staff, especially as NZ Post managed an increase in the number of parcels.
NZ Post has 68 employees throughout Northland but none work specifically in FastPost service.
Last year about 6600 items were sent from Whangarei through FastPost and about 33,000 sent to Whangarei using the same service.
For business customers a new priority mail service will be available in and between Auckland, Wellington and Christchurch.
"New Zealand Post will continue to seek ways to improve efficiency and make cost savings to maintain a commercially viable postal network and to give our customers the best possible service."