Operating under Covid-19 Ministry of Health restrictions, New Zealand Post has restricted its courier services from Northland to Auckland and Waikato because of overwhelming demand.
Since the beginning of the year, 219,037 parcels have been sent from Whangārei into Auckland and 48,403 into Hamilton.
An NZ Post spokesperson said that with changing alert levels, the postal service had seen and was continuing to see significant increases in parcel volumes in the network, and the capacity had been exceeded by customer demand in some areas.
"Over the last five weeks, NZ Post has delivered around two million courier parcels each week – and are on track to do the same this week. This is over half a million additional parcels delivered each week to what we normally deliver.
"In Auckland, where we are seeing the largest parcel growth, we are delivering 695,000 items per week, compared to 440,000 per week prior to entering alert level 4 - a 58 per cent increase.
"Our courier network service is under extreme pressure in Auckland, with delivery delays of up to five working days.
"With the evolving Covid-19 situation in Northland and the Waikato region, we are also expecting increased parcel deliveries and possible delays there too."
NZ Post was implementing several initiatives across its business to help manage the volume of items accepted into the network in line with what it could reasonably deliver.
The postal service encouraged its customers to send via NZ Post Economy Service any parcels under 3kg destined for Auckland or Hamilton.
"Encouraging consumers to send via economy into Auckland and Hamilton not only offers consumers a better customer experience right now but also supports us to keep the maximum number of items flowing through our network efficiently for everyone.
"This is a temporary situation and we want to assure New Zealanders we are working hard to scale our operation further as quickly as possible."