New figures reveal that more than 2,500 positions nursing and midwifery vacancies were unfilled in June, pushing the vacancy rate up to 4 per cent, compared to just 1 per cent in 2011.
Hundreds of positions have been lying empty for more than three months, while mental health, district nursing and health visiting had the highest number of vacancies.
A recent survey found only a quarter of Scottish nurses and midwives felt there were enough staff to allow them to do their job properly, amid warnings of a “workforce crisis”.
The Scottish Government spent £23 million last year on costly agency nurses to plug gaps, despite record numbers of staff working in the health service.
Nursing leaders said staffing levels were not keeping pace with demand, which could be putting patient care at risk.
Royal College of Nursing (RCN) Scotland associate director Norman Provan said: “We know that health boards are struggling to deliver services to more and more people, with budgets which are not keeping pace with increasing demand for services.
“This does not bode well for patient care in the future, nor for existing nursing staff who are already under a huge amount of pressure at work.”
Consultant vacancies have fallen for the first time in five years, with 7.5 per cent of sitting empty posts compared to 8.3 per cent last year.
The total number of NHS staff in Scotland has fallen slightly by 0.2 per cent in the three months from March to June 2016 but shows an overall increase of 0.5 per cent year on year.
Labour health spokesman Anas Sarwar said: “We are seeing a workforce crisis in our NHS. The Royal College of Midwives has previously said Scotland is facing a staffing ‘timebomb’ in the profession and we are starting to see real problems.
“This can’t be another problem that the SNP brush under the carpet and ignore until it becomes untenable.”
Health Secretary Shona Robison said NHS staff numbers had increased significantly but work was underway to help boards plan their nursing and midwifery workforce.
She said: “As we increase the workforce we expect to see vacancy levels fluctuate given the natural turnover of staff in an organisation of this size.
“Fluctuations are also caused by increased number of posts available. However, we are committed to working with health boards to help them minimise long-term vacancies.”