Spending through Paymark showed a 72-per cent drop below year-ago levels on March 26, the first day of the Level 4 restrictions.
Prior to the COVID-19 alert level 4 lockdown, however, spending showed a 50 per cent increase from the previous corresponding period.
The Paymark electronic card data showed a 51.8 per cent rise in food and liquor spending in the week ending March 22, and an 81 per cent spike on pharmacy spending.
On March 23-24, just before lockdown spending soared, increasing by around 50 per cent compared to a year ago.
The stock-up was especially noticeable amongst liquor outlets, hardware and homeware shops and recreational goods stores, hinting at activities planned for the coming days and weeks.
Retail spending then remained down by similar levels for the rest of the week ending Sunday.
By Thursday, Paymark said there were a few merchants with payments still exceeding year-ago levels, such as electricity companies and consumer finance suppliers.
There was a slightly larger group with still significant volumes of spending but now at levels below last year. This group includes supermarkets, fruit and vegetable shops, pharmacies, gas suppliers, telecommunication services, security firms, churches and charities. But by far the largest group comprised those merchants who are barely transacting any payments now.
Paymark said travel companies, entertainment firms and parking services were in the negative in the first four days of Level 4 restrictions as they had to give money back to their customers.
Non-fuel spending through Paymark totalled $907 million for the whole week. This was 33 per cent below the previous week and, on an underlying basis, 27 per cent below levels of a year ago.
Spending over the week was up on last year amongst supermarkets and pharmacies but down sharply in total for accommodation providers and cafes, bars and restaurants.
According to Paymark, the pre-lockdown spending splurge was not enough to offset the loss of sales later in the week for most merchants as spending declined to 28 per cent below year-ago levels across the non-food retailers, excluding pharmacies.
In total, the spending decline for the week was largest in Otago (-39.8 per cent), followed by the two major centres Auckland/Northland (-32.4 per cent) and Wellington (-29.6 per cent).