The winning ticket was sold at the Grand Superette in Orewa, north of Auckland.
Owner Harkesh Arora said it was very exciting to have sold such a huge prize as his store has been selling Lotto tickets only since September.
"We had a Lotto rep come see us today and he said we were very lucky to have sold a winning Powerball ticket in just three months of selling Lotto.
"He said some stores had been selling Lotto for 10 years and still hadn't sold a big winner."
Mr Arora said he had been out celebrating the coming New Year with friends on Saturday and had not really given a thought about the big Powerball prize up for grabs.
"We had to be at a friend's house for a New Year's Eve party so we just quickly closed up and went out," he said.
"We finished partying in the early hours of the morning and I got only a little sleep.
"I opened the store at six o'clock, half asleep, and went to check the emails and it said we had sold the Powerball.
"I was wide awake after that - and I thought, 'Oh, I must check my ticket'," he laughed.
Mr Arora wasn't lucky this time.
He hoped the ticket had been sold to one of his regular customers but it may have been bought by someone passing through.
"They haven't come in to claim it yet. Usually people don't like to come claim it at the shop, but I hope they do," Mr Arora said.
"I'd love to have a chat with them."
Two other tickets won $1 million in Saturday's Lotto holiday promotion.
One ticket was sold at the Ashby Superette in Auckland and the other at the Northwood New World supermarket in Christchurch.
