Staff shortages led the trust which runs Pontefract Hospital to spend £13m on temporary workers in just six months.
The figure – £13,006,036 between April and September – for staff including locum doctors and agency nurses, is nearly double the amount spent in the same time period last year.
Mid Yorkshire Hospitals NHS Trust is now spending around £2m a month on temporary staff.
A report to the trust board last week said temporary staffing costs equated to 9.12 per cent of staff costs, with the highest costs within accident and emergency departments and medical and dental staff.
Adrian O’Malley, hospital trust Unison branch officer, said: “This is outragoues and should be investigated. No matter how good agency staff are, they don’t know the trust and it heaps more pressure on permanent staff.”
Separate figures show the number of nurses and midwives had fallen by 200 between March 2012 and this August, although trust bosses say 200 nurses have been hired during a recruitment drive.
Graham Briggs, human resources director, said temporary staff spending was kept to a minimum and it was currently recruiting staff.
He said: “It reflects difficulties currently experienced by hospitals across the country in recruiting permanently to specialist medical and nursing posts.
“It is absolutely vital we have people at the trust to provide this type of care.”