The state government has amended the Public Lottery Licence to increase the Oz Lotto matrix from seven from 45 numbers to seven from 47 numbers.
Three supplementary numbers will be drawn instead of two, resulting in 10 numbers drawn from 47.
The changes take effect on May 11 and decrease the odds of winning first division from one in 45.3 million to one in 62.8 million, the Victorian government gazette says.
The move will affect Oz Lotto entrants in all states and territories since the Victorian-licensed game is played nationally every Tuesday.
Opposition gambling spokeswoman Steph Ryan accused the government of making a cash grab because the changes would lead to more tax revenue for Victoria.
"By adding extra numbers to the lottery, the government is ensuring that it's harder to win, which means it's going to jackpot more and bigger jackpots lead to bigger ticket sales," she told reporters on Thursday.
"This is just another desperate grab for cash from the Andrews government to try and plug its failure to manage its own budget.
"It's hard to imagine a more stingy move than making Oz Lotto so much harder to win."
Sport and Events Minister Martin Pakula dismissed concerns the game would be harder for punters, saying the differences in winning were "pretty academic".
"I've played TattsLotto ... for 30 years and I've never won first division and probably never will," he told reporters.
19°C