Two Australian households were in shock yesterday after winning the nation's biggest-ever lottery jackpot, worth more than $100 million.

An estimated 10 million people purchased tickets for Tuesday night's much-anticipated Oz Lotto draw, with frenzied sales driving the scheduled $90 million top prize to more than $106 million, officials said.

A long-time lottery player from Adelaide, capital of South Australia state, and a Gold Coast couple who had never bought an Oz Lotto ticket before picked the lucky nine numbers. Each won more than $53 million.

The winners expressed amazement that their one-in-45-million chance of snaring a fortune had paid off.

"I'm numb and quite frankly I have no idea how I'm ever going to sleep again," the middle-aged Adelaide man told lotteries officials, according to a statement from SA Lotteries.

"I never expected to win, and certainly never expected to win more than $50 million. I couldn't move, I couldn't react, I couldn't do anything but sit there and stare at my ticket," the unnamed winner was quoted as saying.

The couple from the Gold Coast, in northern Queensland state, had checked their numbers "multiple times" overnight and waited by the phone for officials to call, said lotteries spokeswoman Karen Anning.

"(But) it's business as usual for them today, they are going to work," she said.

Lottery websites were flooded with traffic and crashed immediately after the draw, which included the unusual consecutive trio 21, 22 and 23. Punters spent more than $209 million on tickets, with huge queues reported at shops across the country in the hours before entries closed.

The 106-million-dollar jackpot eclipsed Australia's previous record lottery payout of 58.7 million dollars, which went to a workplace syndicate in Melbourne last month.