About 200 parcels a minute went through the NZ Post network in the first two weeks of alert level 3 - a 105 per cent increase in online shopping during that time.
New research from the state-owned postal service reveals New Zealanders spent more than $200 million as the country moved to alert level 3 and it received a total of 3.5m parcels in the first two weeks of the move, which opened up to allow e-commerce deliveries of non-essential items.
Online shopping peaked in April, and while the uptake in e-commerce has since levelled out, NZ Post says the online spend continues to be up 30 per cent on this time last year.
Online spending now accounts for 11.6 per cent of all retail sales, up from 9.8 per cent, according to NZ Post.
In 2019, $1 in every $10 was spent online. During alert level 3, $1 in every $4 was spent online.
Typically, NZ Post would deliver an average of 250,000 items per day, but volumes surged to more than 500,000 on the first day of alert level 3 and continued for 10 days afterwards.
Chris Wong, NZ Post general manager of marketing, said the volumes of parcels through the network during alert level 3 were double that of expectations.
"That 11.6 per cent of total retail was the average for six months," Wong said, adding that early indicators showed that online shopping behaviour had changed.
"Post-Covid levels are much higher than it was pre-Covid, but how things like the economy and any recessionary effect later in the year, we don't know how that is going to play out [for sustained online spend]," Wong told the Herald.
"Our prediction is that we will continue to see online grow as a share of total retail ... in other countries it is up around 20 per cent of all retail, so we're a little bit behind from that perspective, but we expect it to continue to grow - it had a big acceleration through the Covid period."
Wong anticipated that New Zealand was still "a few years away" from reaching the 20 per cent mark, but the postal service planned to invest in infrastructure to expand its capacity.
During alert levels 3 and 4 NZ Post experienced a delay in processing parcels through the system, with New Zealanders reporting lengthy delivery delays.
NZ Post will invest $170 million over the next five to 10 years to double its network capacity, including opening more sorting centres, Wong said.
"The volumes we are experiencing now were predicted to be a few years away so we are accelerating an investment in our network.
"There will be new sites and new automation that we'll be putting through the country because we are picking that [the uptake in online shopping] is going to keep on going and we are going to need to do that to maintain the level of service we provide."
It is currently building a "super-depot" in Grenada, Wellington, which it expects to be operational in 2022 and 11 other different sites throughout the country.
"With that we'll have to see our delivery capacity lift as well as volumes grow."
Findings in the research show that 71 per cent of the retail spending so far in 2020 is with domestic retailers, Wong said more shopping was also now happening domestically.
Separately, 170,000 Kiwis started shopping online for the first time this year - the largest proportion of these were Kiwis aged 60 and above - a 65 per cent increase in the same time in May the previous year.
"We have indication that behaviour is continuing."