The Auditor General says £164.4m was spent in 2016/17 alone and has called for strong leadership to manage the situation.
It has been highlighted that skill shortages among staff, increases in patient demand, and the rising levels of sickness absence in the NHS have contributed to the situation, and that 82% of agency spend so far in 2018/19 has been for covering vacancies.
One problem noted to have exacerbated the situation is the rates of agency pay, the rise of which has been fuelled by competition between health boards in their desperation to make up the staffing shortfall.
Commenting, Welsh Conservative and Shadow Minister for Health Angela Burns AM, said:
“We are facing a staff recruitment and retention crisis in Wales because Labour ministers have consistently failed to make working in the Welsh NHS attractive to healthcare professionals from both inside and outside Wales.
“This is a result of two decades of mismanagement: we need better workforce planning to avoid a shortfall in permanent staff with the correct specialisms.
“The problem is particularly chronic in rural Wales, leaving the health board in the West racking up huge financial deficits and that in the North in the perpetual purgatory of Special Measures.
“This growing dependency on agency staff shows NHS Wales is in an unsustainable state and it is the Welsh Labour Government who must take responsibility for this.”