For days after an $80 million Powerball draw, a Melbourne couple ignored the ticket stuck on their fridge door - but when they finally made time to check it, they found themselves $20 million richer.

The grandparents in well-heeled Brighton, one of the most affluent suburbs in the state, held one of the four division one winning tickets in the Powerball draw last Thursday, pocketing a $20 million slice of the overall $80 million pie.

However, their ticket was unregistered, meaning officials had to wait for them to claim their prize, which took a few days.

"This is unbelievable. We had no idea, and this whole time the ticket was just sitting on our fridge," the grandmother said.

"We've both been really busy, so we just forgot to check it."

She said the couple would look after t

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