The number of agency nurses used by the NHS in Scotland has more than doubled in five years, according to a Scottish Accounts Commission report that calls for trusts to reduce dependency on temporary staff through better planning.
The commission estimates that employing bank and agency nurses costs the service about£25m a year.
More than 10,000 nurses are thought to be registered with nurse banks and an average of almost 540 agency nurses are used every day.
Commission director of health studies Caroline Gardner said: 'Although bank and agency nurses are important to trusts in filling unforeseen gaps they should not be the first option considered when staffing problems arise.
'Other less expensive options, which maintain continuity of care for patients, are available and should be considered first.'
The commission carried out a review of the use of temporary nurses at 36 trusts. Most had more than one nurse bank and one trust operated 10 nurse banks.
Only two trusts used a computerised system to match the demand for bank nurses with their availability.
Most trusts did not have a contract with a single agency but made ad hoc requests to various agencies for temporary staff, which meant they paid a higher rate.
The commission warned that trusts needed to ensure that rigorous pre-employment checks were carried out on nurses and that new temporary staff went through an induction and appraisal process in order to safeguard quality of patient care.
Temporary Measures - managing bank and agency nursing staff.