"Who is this? Why are you calling this late?," the winner reportedly said when contacted by Oz Lotto operator The Lott.
"You better not be pranking me! I don't know whether to believe you or not."
The woman, who had bought her lottery entry online, was the only person to get a division one - getting all seven numbers correct - win.
The $100 million jackpot is the largest for a single winner in Oz Lotto since it started in 1994.
An Adelaide man became Australia's largest-ever individual lottery winner in May when he took sole claim to a $150 million Powerball prize.
"Internally, I'm sweating bullets! Are you sure this is real? Oh my gosh. I still can't believe it," the winner of the Oz Lotto prize said on Tuesday night, according to The Lott.
"That's crazy! I just finished watching tonight's episode of Married at First Sight and I was falling asleep as you called me.
"It's 10pm here and when I saw multiple missed calls, I thought, 'Who would be calling me at this time?' I was worried something was wrong!
"I still feel like I'm being pranked or I'm dreaming."
She said the $100 million would allow her to buy a house of her own.
"I love my job but I won't need to work seven days a week anymore. It's actually really nice to think that I won't need to work!" she said.
"I'll finally be able to buy a place of my own. It's so exciting. I'll start treating myself more. I'll go on some holidays!"
Gambler's Help puts the chance of taking the first-division Oz Lotto prize at less than one in 62 million.
That compares to an estimated one in 1.2 million chance of getting hit by lightning in any given year, according to US researchers.
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