The 90km orbital rail line is Victoria's most expensive infrastructure project, designed to run from Cheltenham in Victoria's southeast to Werribee in the southwest via Melbourne Airport.
The first two stages of the major rail transformation, SRL East and North, will cost an extra $9 billion to build and maintain and $7.5 billion to run over the next 50 years, according to the Victorian Parliamentary Budget Office.
The report, commissioned by the state's opposition and released on Tuesday, is an update to its 2022 report that estimated the build and operational costs for the first two stages would cost $200 billion.
The 26km SRL East running from Cheltenham to Box Hill, which began construction in 2022 and is expected to begin operations in 2035, is predicted to cost $33 billion to build.
The budget office projects an additional $51 billion on top of that to operate until 2084.
The 19km second stage SRL North, running from Box Hill to Melbourne Airport, is expected to have a price tag of $63 billion to build and cost $69 billion to operate.
The $216 billion cost is only for the first two stages, which covers two-thirds of the project, and does not account for the final phase which includes Melbourne Airport to Werribee and the airport line.
The transformational rail project was announced in 2018 with a price tag of $50 billion for the entire rail line.
The state government has pledged $11.8 billion to build the eastern section with an additional $2.2 billion from the federal government, and the remainder is expected to come from "value capture" revenue.
Opposition Leader John Pesutto has promised to pause the project if elected in 2026.
"This is a project Victoria simply cannot afford," he said.
