Treasurer Michael Ferguson announced the figure on Tuesday, also revealing the 2024/25 budget, to be handed down on Thursday, would predict ballooning net debt of $8.6 billion in 2027/28.
The Liberals inherited zero net debt when they came to power in 2014 and have resisted recent calls from an independent economist to reduce infrastructure spending.
The 2023/24 budget papers forecast net debt to reach $5.6 billion in 2026/27.
The government is implementing 191 recommendations from an inquiry into child sexual abuse in state institutions, which delivered its final report in September 2023.
Mr Ferguson said the government's total commitment to the reforms was $1.1 billion, but the final figure could be greater.
He said the 2024/25 budget would include $423 million to help deal with "40 years of failure".
"This will be expensive, this will hurt the budget but it is necessary to attempt to heal the wounds of the past," he told reporters.
There are 54 legislative reforms, including the establishment of a new commission for children and young people.
The inquiry found Tasmanian government had too often responded inadequately to allegations or instances of child sexual abuse over decades.
It was told harrowing accounts of abuse at the operational Ashley Youth Detention Centre, which the inquiry recommended be shut as soon as possible.
The government is aiming to close the centre in mid-2026 and replace it with more therapeutic facilities but has conceded the deadline may not be met.
In 2021, the government promised to have the centre shut by the end of 2024.
Tasmania's liability for current and future redress claims by survivors jumped from $130 million in June 2023 to $647 million in June 2024..
The state in June reached an in-principle $75 million settlement with 129 people who were allegedly abused at the detention centre between 1960 and 2023.
Mr Ferguson on Sunday announced the budget would include $5.1 billion for infrastructure over four years, about $100 million more than the previous budget.
A report by economist Saul Eslake questioned whether Tasmania could afford its infrastructure program, on track to be the nation's largest relative to state size.
Revised figures put the state's budget deficit at $1.5 billion for 2023/24 rather than the forecast $297 million, largely due to the redress liability.
1800 RESPECT (1800 737 732)
National Sexual Abuse and Redress Support Service 1800 211 028
12°C