More "formal recognition" of support clinical workers is needed ahead of the publication of the Francis report, a health figure has said.
Richard Griffin, director of the Institute of Vocational Learning and Workforce Research (IVLWR) said lack of registration makes "little sense".
He said: "Too often the most vulnerable in society are supported by staff with the fewest qualifications.
"Increasingly they are directly caring and supporting patients and clients. The lack of registration is something we hope the Department of Health will address."
A Department of Health spokesman said: "We are keeping the situation under review but currently we believe that health support workers can be effectively supervised by professionally qualified staff and experienced nurses.
"Regulation of healthcare workers in the NHS is no substitute for proper performance management, good leadership and day to day high quality patient care."
Griffin said that high quality education and training are key to delivering safe and effective care.
The Francis report into patient neglect at Mid Staffordshire NHS Foundation Trust is due to be presented to the Health Secretary.
The report will examine why serious problems at the Trust were not identified and acted on sooner.