The federal auditor-general has slammed the management of Australia’s biggest renewable energy project, Snowy 2.0, citing multiple failures and pointing to yet more delays for the project that is already vastly over budget.

The report by the A-G, released on Thursday, is the first to be completed since Snowy Hydro announced a project “re-set” in 2023 that conceded the costs of the huge pumped hydro facility had blown out to $12 billion, and faced yet more delays, pushing the expected completion date out from May, 2026, to the end of 2028.

The project costs appear set to blow out once again to around $20 billion, and some argue that the total costs including interest and transmission is closer to $40 billion. The full extent will be revealed soon after an intensive none-month, line by line analysis of project costs.

The A-G report is critical of the actions of both the board and the management since the re-set.

“Since then, (management) has not effectively held the contractors to account for delivery, has not effectively implemented measures that were intended to manage project risks, and does not have access to quality data that would allow it to appropriately monitor the project,” the report says.