A mental health trust, which is looking to cut 500 jobs, spent more than £3m on locum doctors last year, according to new figures.

Critics of Norfolk and Suffolk NHS Foundation Trust's plan to reduce front-line staff numbers as part of a restructure yesterday described the sum spent on temporary doctors as 'mind-boggling'.

Figures from a Freedom of Information request reveal that the NHS trust spent £3.2m on locum doctors in 2012.

It comes as the mental health trust is planning to cut 502 out of 2,128 posts and 20pc of its inpatient beds by 2016 in order to balance its books.

Norfolk and Waveney Mental Health NHS Foundation Trust and Suffolk Mental Health Partnership NHS Trust merged at the beginning of 2012 and the new organisation is looking to reduce 5pc from its budget every year over the next four years because of reduced funding.

The two trusts spent £3.1m on locum doctors in 2011.

Bob Blizzard, Labour's prospective parliamentary candidate for Waveney, who is campaigning to save inpatient beds at Carlton Court Hospital in Carlton Colville or at Northgate Hospital in Great Yarmouth, said £3m seemed like a lot to spend on locums.

'They are saying they can function with 500 fewer critical staff and yet at the moment they have staff shortages. It is mind-boggling. It is the same with beds. How are they going to do with fewer beds when the existing beds do not meet demand?' he said.

Concerns were raised by the doctors' union British Medical Association earlier this year after it emerged that consultant doctor numbers at Norfolk and Suffolk NHS Foundation Trust could be cut by a third and other grades of doctor reduced by 40pc over the next three years.

A BMA spokesman yesterday said: 'These figures indicate that the system is already under strain. The planned cuts to numbers of doctors will inevitably increase that strain. That means the trust will either need to spend even more on locums, cover the shortfall with non-medical staff, or reduce quality or access to services.'

A spokesman for the mental health trust said: 'In recent months we have not recruited to all vacant posts in a bid to minimise the number of compulsory redundancies we may be required to make as a result of the service strategy.'

'While doing this we are also working closely with services across Norfolk and Suffolk to help them reduce the number of locums used.'