Now that the Melbourne Cup is over, Australians have turned their focus to the Oz Lotto's $100 million pot prize up for draw on Tuesday night.

The biggest ever jackpot Lotto prize in Australian history, Lotterywest, an Australian lotteries firm operated by the Western Australia state government, said the big draw has created a mixture of excitement, frenzy and anticipation across the state.

"Our retailers have been reporting an extremely busy few days, with today expecting to get even busier," Pina Compagnone, Lotterywest spokesperson, told Perth Now.

"We expect about 1.4 million tickets to be sold in WA for the draw and during peak times, between 4pm and 5pm, we estimate about 1,500 tickets to be churning out of Lotterywest terminals every minute."

Earlier at lunch time, The Herald Sun reported punters from South Australia omitted taking lunch to spend time lining up at newsagencies, delis, clubs and pubs to place a bet.

A spokeswoman for Tatts Lotteries told The Australian it had lodged a record eight million-plus entries already, and counting, which meant more than one ticket for every three Australians.

"Sales have been bigger than anticipated, and we had anticipated very big sales," the spokeswoman said.

To win the $100 million jackpot, punters need to choose seven numbers between one to 45, which later on should match the seven winning numbers. One set of seven numbers costs $1.20.

Historically, the numbers 27, 25, 40, 6, 33, 35 and 28 have been the most frequently drawn numbers for the Oz Lotto.

"You've got to choose seven numbers out of 45. There are, roughly speaking, 45 million ways of doing that; 45,360,620 I think is the exact number," Professor Peter Taylor, an applied mathematician at the University of Melbourne, told World News Australia. The odds based on 18 games is 2,521,090 to one, he added.

"I want to go around the world," Elizabeth Uzelac, of Hallett Cove, who spent $200 on tickets, told The Herald Sun when asked what she would do if her numbers were chosen as the winning combination.

"The draw coinciding with Melbourne Cup Day means there is a lot of excitement in the air as people place their bets on the horses and pick the seven numbers they hope will come up in Oz Lotto tonight," NSW Lotteries spokeswoman Zoe Knobel told Nine News.

Punters have until 7pm tonight to purchase tickets for the draw, which will be drawn at 8.30pm Adelaide time.