The trio was "absolutely stunned".
"I raced around the house to check my ticket on every phone and computer we could lay our hands on," the winner said.
"I must have logged in and checked it 100 times that night."
The woman decided to buy a ticket as the proceeds were going to quake-ravaged Kaikoura.
"I was out shopping with Mum when she stopped by the supermarket to pick up a few things for dinner, but it was raining and miserable so I decided to stay in the car.
"That's when I remembered about Saturday's special Lotto draw for Kaikoura, so I grabbed my phone and bought a ticket on MyLotto."
She planned to use some of the money to reunite her family for the first time in more than a decade.
"My siblings have been living overseas for years now, working hard to try and save enough to come back home one day, buy a house and be close to our parents again.
"When I found out I'd won, I knew I could help them out, so I video called them to share the good news. I was in tears when they picked up the call, so they immediately thought something bad had happened.
"That's when I managed to squeak out between sobs 'I've won Lotto - and I'm giving you $1 million'," said the winner.
"It took a bit of convincing, but when they realised I wasn't joking they just lost it."
She also planned to have a "little shopping spree", go out for a nice dinner with her parents and pursue her passions, including helping animals.
"Other than that, I'm not too sure what I'll do with my winnings. At the moment, I'm just looking forward to everyone coming home.
"This win is a real gift and I want to make it last."
She said she might still buy the odd Lotto ticket.
It was the third Powerball First Division prize won by a MyLotto player so far this year.
The $2.7 million raised through the draw is going to Kaikoura, Hurunui and Marlborough to help with the quake recovery.