The Public Service Association says a disclosure that a public sector cost-cutting exercise is struggling to come up with the annual savings expected of it, are proof there's little left to cut from budgets.
The Treasury last year identified potential savings of $236 million from the back office functions of 33 departments.
These would be achieved by bringing efficiency up to the average of the private sector in information technology, property, corporate and financial services, and human resources.
In 2010, departments made savings of $87 million and a report due to be issued on Wednesday will show only $20 million of new savings was found last year. Some of the details were outined on Friday by the head of Treasury.
Gabriel Makhlouf said progress is being made, but more needs to be done to achieve the savings targeted.
However, the Public Service Association says that might not be possible.
National secretary Brenda Pilott says budgets are stretched and more cost cuts will hit frontline services.