Extra staff needed because rubbish collectors work on average two hours less than required every day are costing taxpayers more than $85 million a year.
The report found that the 615 staff hired by the Regional Services Department (RSD) to work 7.5-hour shifts regularly left work as soon as their task was finished - after an average of 4.7 hours.
Of its 148 teams and collecting vehicles, 30 per cent were surplus to requirements, the auditor said. This wastage cost an estimated $85.3 million in 1997.
The low rate of contracting jobs out to private collectors was an additional source of wastage, the report said.
Up to $112 million could be saved if the department contracted out 50 per cent of its refuse collection, it said.
'The daily workload was overestimated by 19.9 per cent.