OfficeMax Whangarei account manager Simon Millar and retailer Maree Pulham presented the prize, $1000 worth of office products for Mrs Cox's class, a trophy and bunch of flowers.
The presentation took place in front of the entire school of 90 children, including Mrs Cox's five, her youngest daughter Samantha presenting part of the prize to her proud mum.
"You do an amazing job with these kids," board of trustees chairman Mike Crammond said.
"It's a special day for you and the school, recognising what you do. Congratulations. And thank you to Office Max for acknowledging the teachers and recognising what they do."
Principal Carolyn Smith was equally thrilled.
"It's fantastic," she said. "We have six teachers in this school who are worthy for nomination. It's a shame we couldn't have nominated them all. And the fact it is not a popularity contest but is judged by her peers, I think it's great."
Mrs Cox has been teaching since 1995 and at Pukenui for the last five years. She said she had always wanted to be a teacher, an ambition she remembered her primary school principal supporting.
"I love children. The joy is challenging the kids at their level and watching them succeed," she said.
"I feel that there are so many other people who are worthy. Teachers do so much. It is such a lovely feeling you get when you see the students progressing. That's why we do it, but I'm certainly not exceptional."
She worked with an "awesome" team - "Everyone here is so dedicated" - and was both very honoured and embarrassed by the award.
OfficeMax New Zealand's general manager (education), Suzanne Flannagan, said the programme was now in its sixth year globally,and the standard had been climbing ever since it was introduced in New Zealand.
"We adapted the global 'A Day Made Better' programme, which began in the US in 2007, to really make it New Zealand's own by rewarding primary and intermediate teachers who are known for their passion and enthusiasm and for continually inspiring their students," she said.
"The response has been amazing. We are so fortunate to have such high-calibre teachers in this country, and while it is obvious the principals are grateful for their hard work and dedication, it's the outside recognition that really surprises them."