The couple quickly jumped into their car and headed to the store to check their ticket.
"The store was so lovely - they were genuinely thrilled for us and gave us a bottle of bubbly to celebrate."
While the winners were still in "disbelief", they spent the Sunday afternoon eyeing up new cars at the car yard.
They celebrated on Sunday night with a traditional Kiwi feast - fish 'n' chips.
"We cracked open the bubbly with our fish 'n' chips for dinner on Sunday night - we added oysters to our order to make it a little fancy," the winner said.
The newly minted millionaires were also thinking about buying a new house before embarking on a summer holiday around the country.
"It still feels so unreal. I haven't slept in days!" the winner said.
The winning Powerball ticket was sold at South Dunedin Night N Day and is the third Lotto First Division ticket bought from the store in the past four months.
This is the second major First Division prize to be won in Dunedin this year.
In July, a ticket sold at Pak'nSave Dunedin won $13.3 million, after the $40 million must-be-won Powerball prize rolled down to Second Division, where three winners split the jackpot.