Regulations do not specify the method of conducting the health assessment. It might be conducted by a qualified medical practitioner, but it could consist of a health questionnaire assessed by a health professional, such as a nurse.

The purpose of the assessment is to identify any factors that might be detrimental to the health of a worker as a result of nightwork, in which case he or she is entitled to be transferred to suitable day work where this is possible.

In such a situation, regulations provide that a 'registered medical practitioner' must have advised the employer that the worker is suffering from health problems that the practitioner considers to be connected with the performance of nightwork.