The rapid rise in online shopping has prompted NZ Post to lease a $100 million-plus yet-to-be-built premises the size of three rugby fields in south Auckland.
The state-owned enterprise said the 3.3ha planned new building would be in addition to its planned new Wellington "super depot".
A spokesperson said the both Wellington and Auckland buildings were in response to the rise in online shopping.
"NZ Post is investing in infrastructure to meet the growing demand for online shopping and parcel processing and delivery. The investment programme began in June with the start of construction of a new super depot for parcels, in Grenada, Wellington," the spokesperson said.
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"The programme also includes a new processing centre in Wiri, South Auckland, due to open in 2023. Blessing of this site will be taking place in the coming weeks, with construction to start soon after," NZ Post said.
The SOE is investing $170m in its network to double its parcel-processing capacity from 95m parcels a year to 190m parcels and Associate State-Owned enterprises Minister Shane Jones announced the Wellington depot in June.
In May, Broadcasting Minister Kris Faafoi said without Government support, NZ Post would face having to make drastic cuts to its mail business to remain viable.
"Post's revenue has fallen substantially but the costs of delivering the service New Zealanders expect have remained the same. The $150m equity injection, along with the $130m funding for mail services, means we avoid significant cuts to its service and workforce and big price increases for its customers," Faafoi said at the time.
Last September, NZ Post reported a loss of $121m in the 12 months ended June 30, compared to a profit of $13m a year earlier when the bottom line was buoyed from its share of Kiwibank profits.
Tony Catton, New Zealand senior development manager at Sydney-headquartered property specialists Logos, said his company would build the new premises.
The site would be worth about $600m once a number of new buildings went up there, said Catton, who previously worked in property for supermarket giant Foodstuffs.
The Wiri building is in addition to NZ Post's existing handling centre at Highbrook.
"This is an addition to the processing centre network and will be for international parcel sorting and distribution to respond to the anticipated growth in New Zealand business, particularly online sales," Catton said.
Logos plans to soon start work soon on the site owned by a pension fund, AustralianSuper.
Catton said Logos would build 33,700sq m premises which NZ Post has agreed to lease for 20 years from 2023.
Other businesses have also signed up to lease as-yet-unbuilt premises there.
Hilton Foods New Zealand has committed to a 25-year pre-lease for a 15,700sq m processing and distribution buildings.
Catton said development work started at Wiri last April.