Victorian Treasurer Tim Pallas has vowed to prove the credit-rating agencies wrong, as he claimed a $1.5 billion contingency provision set aside in Tuesday’s budget is not a secret but provides wriggle room for major projects and deals with the federal government on health and schools.

Mr Pallas delivered a $15.2 billion deficit on Tuesday, and net debt will grow from $156 billion next year to $188 billion by 2028.