A report by the Comptroller and Auditor General is expected to raise concern over a lack of transparency in the way voluntary groups in the disability sector spend almost €1 billion of taxpayers' money.
An unpublished draft of the report, seen by The Irish Times, found that levels of executive pay were not generally reported by voluntary groups in a transparent manner.
It also uncovered widespread failure to file proper financial accounts.
An audit of 42 voluntary - or non-profit - organisations between November 2004 and January 2005 found that in 12 cases bodies did not file accounts for 2003. These groups received approximately €100 million during the same year.
It also noted several cases where financial statements carried qualified audit opinions due to uncertainty over issues such as the verification of fundraising amounts.
In the case of one major voluntary body, it found that no financial statements had been received for four years.
The group continued to receive €210 million over the same period.
Expenditure on headquarters costs, overheads and executive pay was not generally reported in a transparent manner which made it difficult to assess whether charges were reasonable, it found.
The report also says the Health Service Executive failed to specify desired outcomes in its service agreements with voluntary groups.
This, it notes, militated against the evaluation of the overall effectiveness of procurement of services through non-profit organisations.
In the area of disability there has been no review or evaluation of services with any HSE region or on a national basis into the procurement of services from the voluntary sector, according to the report.
The C&AG draft report calls for a strategic review of funding relationships with voluntary service providers, along with greater monitoring of the population in the catchment area of a voluntary body.
In one voluntary group, the report notes, the number of clients treated decreased to a quarter of 1994 levels while its financial allocation in real terms increased six-fold. In another service, a "custodial culture" had developed due to lack of staff.
In total, €879 million in State money was given to non-profit or voluntary sector groups in the provision of services for people with disabilities.
Some 24 bodies received an average of €24 million, while a further 65 bodies received between €1 million and €10 million. A further 638 groups received grants of, on average, €100,000.
It is estimated that the voluntary sector provides a large proportion of services for physical and sensory disability, and around 90 per cent of services for people with intellectual disabilities.
The report is likely to spark debate over whether Irish services should follow the path of the UK, where there is greater clarity over the link between funding and services being provided.
In its draft conclusions, the report calls for a "clear policy statement" on access to services, to plan for the gap between assessed needs and capacity, and to put into practice standards of care for persons with disabilities.
It says standards of care would focus attention on service outcomes and consistency in quality and performance on a national basis.