It could be in the depths of Borneo's jungle or down the side of the couch, but somewhere out there is a Melbourne-bought Powerball ticket worth $55 million.

It's been two weeks since a mystery person bought the winning ticket from the Scole Lotto & News agency in Brunswick and the first time a prize of this size has gone unclaimed in Australian lotto history.

"It's unprecedented," Tatts spokeswoman Elissa Lewis said.

"We don’t know who purchased the ticket, or anything else about them, all we know is they purchased the ticket from that outlet," Ms Lewis said.

"We can’t contact whoever it is. We have to wait for them to check the ticket, realise it is a winning ticket and then contact us."