One of them noticed on Facebook that evening that the Powerball ticket had been sold at the same store.
"I bolted across the house and told my other sister that we'd bought our ticket from the winning store," said the sister.
"We tried to calm down by telling ourselves that it was probably someone else, but all we wanted to do was check that ticket."
Unfortunately, the ticket was at their sister's house across town and it was too late to call. They had an agonising wait overnight to check it.
"We were sitting in the lounge in our pyjamas watching the rugby, when I got a text from my sister letting me know that Fitzroy had sold the winning ticket and asking whether I'd checked it yet," said the sister who bought the ticket.
"I wasn't in any hurry to check it to begin with, but I could tell from her message that she really wanted me to, so I thought I had better do it."
After checking the numbers, she quickly texted her sister back, saying she "better come over".
"She thought I was joking at first," she said.
"I was so sure she was having us on," said the other sister.
The family rushed over to the ticket-holder's house in their dressing gowns and slippers.
"They turned up on my doorstep minutes later ... I handed them the ticket and we all just stood in the lounge cheering and hugging," said the sister who bought the ticket.
They kept the ticket hidden in a safe for a week before claiming it at Lotto NZ's head office today.
They plan to use the money to look after the broader family, including the generations to come.
"This win is an amazing gift and we want to make the most of it. It's an incredible feeling knowing that our children and grandchildren won't have to count every penny," said the winners.
"I'm sure it will sink in eventually, but for now we can hardly believe it. We feel incredibly, incredibly lucky."
