The man was one of nine division one-winning entries in Saturday's draw.
Postal worker Robert Bailey is a"humble man"who after a quarter of a century won the jackpot.
It is the second-largest division one prize ever won in an Australian lottery,only topped by a $70 million Powerball prize won in 2016.
For the fourth time in just over a week,Canberra has had a big lottery winner - this time a syndicate led by an ACT woman won $200,000.
And one Canberra outlet sold all three of this week's winning tickets,including the latest for $800,000.
Somebody,somewhere in South Carolina,is going to look at their bank balance Wednesday and think:Well,that escalated quickly.
A record-setting $US1.6 billion ($2.26 billion) prize that would instantly make a single winner one of the richest people in the world will be up for grabs on Tuesday when the Mega Millions holds its drawing.
The Wanneroo man was unable to check his tickets until he returned home from work earlier this week,and was shocked to find he was $1 million richer.
The lucky winner was oblivious to the fact that he had accidentally bought two lotto tickets and doubled his winnings.
Moves are under way to ban online lottery-betting organisations promoting so-called synthetic lottery products like Lottoland.
One week after the prize was drawn,lottery officials are still searching for the winner.