NSW Lotteries Head of Public Relations Matt Hart said there's a chance the Orange ticket holder does not know they have won.

Mr Hart said they have attempted to reach out to the winner of the Monday & Wednesday Lotto drawn Monday night, but they've been unable to get in touch.

"I suspect they don't know," he said.

"They're probably at work today thinking 'god I need a holiday' and unbeknownst to them there's a million dollars waiting for them."

The ticket sold at the Prince Street newsagency won the division one prize in Monday's draw 3872.

The numbers drawn were 25, 18, 35, 40, 11, 29 and subs 27, 38. The winner will have all six of the numbers in a row.

The person who purchased a ticket from Greengate is one of three division one winners from last night's draw, all of which are yet to be claimed.

"We're certainly calling on anyone to purchased a ticket to check and call 13 18 68 to confirm their prize," Mr Hart said.