Rural contractors will however continue to deliver parcels and subscription newspapers on Saturdays in areas where there is currently six day delivery.
"Letter volumes continue to fall sharply, whereas the number of parcels and other products in our network is increasing," says Mark Stewart.
Mr Stewart said NZ Post had held off moving to five day letter delivery for all rural customers for as long as possible, however the continuing decline in letter volumes means six day letter delivery is no longer sustainable.
"We're continuing to work hard to bring new business on board to maintain a commercially viable rural network for us and our contractors, and to give our rural customers the best possible service," says Mr Stewart.
"We need rural delivery to be in good shape for the future."