AN MLA has called for a dedicated medical school in the north west after it emerged £13m was spent on locum doctors in the area last year.
The total bill for agency medics across Northern Ireland was £46m.
The Belfast Trust incurred costs of more than £15m for stand-in doctors, while the lowest spend was in the South-Eastern Trust area at £4.4m.
The figures were released in response to an assembly question by the SDLP's Mark H Durkan.
The Foyle MLA said while locum doctors "have a role to play", the amount being spent represents an imbalance in the health system and "makes the argument for the establishment of a medical school in the north west".
"We have been acutely aware of the financial pressures that the Western Trust is under, but a £13m spend on locum doctors can and should be spent better," he said.
"The Western Trust spends much more than three of the other trusts when it has a similar population. This can impact on the delivery of other services.
"Doctors are choosing to live in and around Belfast. It should be more attractive for people to go and work elsewhere."
He added: "Patients deserve continuity and the task of attracting staff to positions in other areas needs to be taken on by central government."
A spokeswoman for the Department of Health said it "will continue to monitor expenditure closely."
"Trust expenditure on agency staff has been incurred to ensure that safe and effective services are sustained and contributes importantly to maintaining service provision to patients and clients," she said.
"Trusts have been asked to examine reliance upon agency staff and the department will continue to monitor expenditure closely."
In March, The Irish News reported that agency staff across the Northern Ireland health service had cost almost £350m over five years - with an 80 per cent rise between 2010 and 2015.
Dr George O’Neill, a Belfast GP, said at the time: "This inflated spend merely reflects the inability of decision makers to reduce our number of hospitals to three or four - until someone grasps the nettle and makes that decision our skilled consultant cover will become diluted."
Last year The Irish News revealed a leaked letter from the head of the Belfast Trust, Dr Michael McBride, warning his most senior directors to urgently curb spending on locum doctors.
