NHS Borders paid £1m for agency staff over the year 2015-16 – a figure the health board claims is the equivalent of 12 full-time nurses.
That revelation comes in the week that NHS Borders came under fire for paying an agency nurse £93.45 an hour for a shift on a bank holiday – which would have cost the health board a total of between £747 and £1,308.
That incensed Conservative MSPs John Lamont and Rachael Hamilton.
Ettrick, Roxburgh and Berwickshire MSP Mr Lamont said: “It is staggering that NHS Borders, which is struggling to balance its books this year, is forking out over £90 an hour for agency nurses.
“This is a slap in the face of hard-working staff nurses who can only dream of such remuneration.
“There is absolutely no reason why health boards should be paying agencies this kind of money.”
However, a spokeswoman from NHS Borders said: “Unplanned activity plays a big part when having to use agency staff.
“Opening extra inpatient beds due to an increased demand for our services can lead to a requirement for additional staff.
“Managing delayed discharges effectively is important as this leads to pressure on inpatient bed availability and there are also cases in which one-to-one nursing is necessary.
“Every option is exhausted before a final decision is made to fill shifts with agency staff in order to provide a safe service.”
List MSP Ms Hamilton said: “Clearly there is a serious issue when agency staff nurses are receiving such disproportionate salaries compared to working staff nurses.
“NHS Borders have little choice however when the Scottish Government is failing to train enough nurses.
“And it seems that the situation is only getting worse with NHS Borders spending twice as much on external agency staff as it did last year.”
The health board spokeswoman said: “The number of hours worked by agency nurses over the course of the year was added up and it equates to 12 full-time nurses over the course of the year.”