"The best moment for me was telling my wife. I'll never forget the look on her face."
The couple said they plan to continue working, and would like to use the $6.5 million to help people in their community.
"That's where our reward will be. There's nothing we really want to splash out on, helping family is our biggest thing."
The $6.5 million Powerball First Division prize was the 13th First Division winning ticket Grant Bros had sold over the years - but its first Powerball win.
Store owner Renee Grant said the store was bustling as customers came in to check their tickets.
"It's really exciting for us. We really want the person to come forward and claim their prize as we know it's going to be absolutely life-changing," she said.
"Everyone is looking high and low for the ticket. Each day the ticket goes unclaimed, more and more people are coming through the door to see if they could be the winner.
"People are also coming in just to buy their tickets from us - I think the word has got out that we are the lucky store in town."
Lotto NZ's general manager of corporate communications Emilia Mazur said it was unusual for a prize of that size to go unclaimed for such a long period, but not unheard of.
In 2014, Hamilton Lotto players searched for a Powerball ticket worth $16 million for 10 days before the winner thought to check their ticket and in 2013, a $22 million prize remained unclaimed in Christchurch for more than three weeks before the winner came forward. He was in no hurry to check his ticket because he believed the prize had already been claimed.