The employers' group IBEC has called on the Government to reduce staff numbers in the public service to save more than €850 million.
The group said the reductions could be obtained in three years through a combination of non-replacement, voluntary retirement and redeployment. The 15,000 suggestion is three times the target of the Government.
Cutting public service numbers, IBEC said, could be used to leverage necessary additional capital spending on vital infrastructure for the State.
"Greater value for money and better quality of service must be achieved in the public service by introducing structural and procedural reforms," IBEC said in a statement.
"These should include increased accountability for performance, the commercialisation of certain activities and the more transparent presentation and publication of information.
"If benchmarking is to achieve its goal of providing better services to the public, the pace and scale of outsourcing to the private sector will have to be increased," IBEC said.
"There is no particular reason why government locally or centrally should be managing its own IT, payroll, training, catering and cleaning services or running the fire service, prisons, ambulances, library services, the processing of road tax and driving licenses or collecting rubbish," the statement added.