The woman then took out her phone and checked the results on the MyLotto app.
"I handed the ticket over to my son and got him to check the ticket too, and we both agreed I had all the numbers. We weren't sure how much I'd won though — we thought maybe a couple of thousand dollars."
It wasn't until the woman went to her local dairy to check the ticket that she found out how fortuitous that free ticket really was.
"I knew something was up straight away because I could see the Lotto lady getting really excited. She handed me over a slip of paper with the prize on it, but I had forgotten to bring my glasses so I couldn't read a thing," she laughed.
She then handed the slip of paper to her niece to read - who lent in and whispered the prize amount in her ear.
"When she said '$1 million' — it was such a shock. Here's me thinking I'd won a couple of thousand. I tried really hard to keep calm in that moment, but I was buzzing inside," said the woman.
With the million-dollar prize arriving into the woman's bank account overnight today, the winner will be waking up in 2019 with a seven-digit account.
"It really hasn't sunk in at all — it's totally surreal," she said.
"I'm just going to take up my time to decide what my next move is, but what I do know is that this prize is going to give me and my family security - and that makes me feel like I've done my job in the world."
The winning ticket was sold at Countdown Dargaville for the Lotto draw on Wednesday, December 26.
This winner joins 47 other Lotto millionaires made from Lotto NZ's games in 2018.