A mathematician is clearly on to something having walked away with his seventh Lotto win.

The lucky Aussie punter, who asked not to be named, has pocketed more than A\$400,000 (NZ\$450,000) in the Saturday Lotto draw after winning the jackpot with 10 other people across the country.

His six other wins were smaller, taking his total winnings to A\$421,753.52 (NZ\$451,452.60).

When called about the win, the thrilled Casino winner revealed his unique method of choosing numbers to a NSW Lotteries official, the Northern Star reports.

"I do a little bit of mathematics and I use a mathematical formula to choose my numbers," he said.

"I heard on the radio years ago that some numbers come out more than others, so I have a spreadsheet that helps me even those out.

"It helps me spread the combination of numbers I choose."

He said he had forgotten to check the numbers for last Wednesday's Lotto, "so I just chose the numbers based on the data I did have".

"Turns out they were the bloody rights ones!"

The man is wasting no time in deciding what he wants to do with his Lotto windfall.

"I've got a shack on a farm and I'm going to pay that off. I'm going to get a ride-on lawnmower so I don't have to worry about mowing acres of land on a push mower," he said.

"Then after that, I might buy myself a new car and get back into some hobbies."

The six winning numbers in Saturday's Lotto draw 3851 were 26, 8, 22, 45, 2 and 12. The supplementary numbers were 1 and 38.

In May, a Melbourne woman who also used "special" numbers managed to buy two winning Lotto tickets. Her total prize was \$9.6 million.

She told a lotteries official she bought the two tickets, one for her and her husband, to celebrate their recent wedding anniversary.

"It was our wedding anniversary and I thought I'd just buy our special numbers on our Set for Life tickets and we'll give it a go. I'll have to take a moment but I just can't believe it. It's a fantastic wedding anniversary," she said.

Her win came just after a Bondi man picked up \$2.5 million after winning the lotto twice in one week.