New figures released by the health service show the number of vacancies has risen by 400 since June, prompting concern about the strain placed on the staff in post.
Nursing and midwifery workers are down by more than 2000 from a peak in September 2009.
Theresa Fyffe, director of the Royal College of Nursing Scotland, said: "Cuts to the workforce are not only bad news for patient care but mean that the remaining staff in the NHS are increasingly over-stretched, and while today's figures also show there has been a slight increase in the number of nursing staff in post over the last quarter, when taken in the wider context it is only a very small improvement."
Scottish Conservative health spokesman Jackson Carlaw said: "Filling these spaces would go a long way towards easing the pressure on those currently in place, and result in better care for patients."
Health Secretary Alex Neil insisted hospitals "must have the levels of staffing and skills to continue to deliver the very best quality care."