Staff at Victorian state schools were paid almost $18 million in stress leave last financial year.

A report by the Victorian Auditor-General reveals that stress leave made up 39 per cent of the $45 million claims by state school staff reported to WorkSafe in 2011-2012, despite being only 22 per cent of the total number.

The audit also found that state schools were not held to account over poor health and safety.

The report stated that stress claims were of particular concern because staff took, on average, more than three times as many days to return to work as those whose claims were classified as musculoskeletal disorders or injuries such as burns or heart attacks.

The report revealed that the number of new WorkSafe claims lodged by state school staff had decreased by 8 per cent over the past three years, suggesting that health and safety in schools was improving modestly.