Countdown is "Aotearoa New Zealand’s leading supermarket brand, serving more than 3 million customers every week."  The first Countdown store opened in 1981.  The chain is owned by the Australian firm Woolworths, and in 2023 announced it plans to rebrand to Woolworths New Zealand.
New World Gardens at 6 North Road in North East Valley.  There more than 140 New World stores around New Zealand.
Four Square Supermarket at 145 Forbury Road in St. Clair, Dunedin.  There are more than 220 Four Square stores run by local operators in communities around the country including about 60 on the South Island.  Also note the adjacent Leckies Butchery, a family business that started in 1927.

Convenience Stores and Dairies
Night 'n Day convenience store on Princes Street.  The franchise firm launched in 1990.
Rob Roy Dairy at 500 George Street (corner of Albany and George Streets).
The 10 O'Clock Dairy at 100 Prince Albert Road in St. Kilda.
Prince Albert Road Dairy at 18 Prince Albert Road in St. Kilda.

Asian Supermarkets
There are many Asian supermarkets in Dunedin.
Sew Hoy Oriental Foods is at 29 Stafford Street.  The Sew Hoy family has a long history in Dunedin (>).
CJ Asian Supermarket at 392 George Street.  See: Jacob McSweeny.  "New Asian supermarket in central city."  Otago Daily Times, July 20, 2020.

Butchers, Fishmongers, Bakeries...
Links Quality Meats at 403 Princes Street offers the "finest cuts in the South Island."  more
Harbour Fish is at 83 Great King Street.