The $7.1 million Powerball First Division was the second huge win for the downtown Lotto shop in recent years after it sold the $27 million Big Wednesday jackpot in 2012.
"I am so happy," she told the Bay of Plenty Times.
Mrs Zeng said it was a double celebration for AJ's because they sold a BMW-winning ticket in the special Christmas promotion. "It's amazing."
Regular customers buying Lotto tickets while the Bay of Plenty Times was in the shop were all philosophical that they had not bought a ticket in Wednesday's draw.
"Who is the clever girl because I didn't buy one," a departing customer said. However, she was not kicking herself, saying, "What it is, is what it is."
Mrs Zeng said the win was good for the shop because it was always followed by more customers buying their Lotto tickets from them.
Lotto NZ spokeswoman Kirsten Robinson said most people came forward within a few days if they had won a big prize.
Some were really quick and had claimed the prize on the same day as the draw while a few were like the $6.8 million Ohakune Powerball winner who forgot he had a ticket in the draw.
The ticket sat in his wallet for eight days before he checked it after hearing "the buzz around town".
Tauranga's unclaimed winning ticket comprised the $100,000 one-tenth share of the $1 million First Division and the $7 million Powerball.
Meanwhile, the winner of a $200,000 windfall who won Strike Four last week is revelling in his success.
The regular Lotto player, who wished to remain anonymous, had been playing the same numbers for a couple of months but had no idea they were sitting on a small fortune until they took their ticket into their regular Lotto shop at Cambridge Heights.
"When the ladies told me I had won a major prize, I was absolutely stunned.
"I've never had so many hugs in my life," the winner said.
"I bought an aged bottle of whiskey to take the edge off," the winner said, laughing.
Lotto NZ advises winners to write their name and address on their tickets and present them to any Lotto shop or bring it to Lotto's head office in Auckland.
Wednesday's nine other First Division winners included a Rotorua punter who had already come forward to claim their prize.
Ten Powerball and Big Wednesday prizes have been won in the Tauranga area, including the $27 million winning Big Wednesday ticket, which was sold at AJ's Lotto in September 2012.
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Tauranga was also home to 2015's 'luckiest' Lotto outlet, Greerton Lotto, which took the title after selling two Powerball First Division winning tickets in 2015.
Lotto advice:
* Anyone who purchased their ticket from AJ's Lotto in Tauranga is encouraged to write their name on the back of their ticket and check it immediately at any Lotto outlet, online at MyLotto.co.nz or through Lotto NZ's ticket-checker app.
* Players can phone Lotto on 0800 695 6886 if they want to enquire about the best way to claim a prize.