The institute has identified 19 guidelines, which if fully implemented could save PCTs up to £800 million. But delegates at the annual NICE conference in Manchester last week warned that many PCTs lack the budget to follow its guidance.

NHS Alliance GMS contract lead Dr David Jenner said it cost PCTs too much up front to follow NICE advice, and savings were slow to appear.

'The NICE chronic kidney disease guidance has increased the number of patients being referred for kidney testing. PCTs are having to employ specialist nurses to meet the guidance.

'As for the depression guidance, my PCT has given up on working out how it can afford it. It recommends 16 sessions of cognitive behavioural therapy (CBT), but many PCTs do not even fund CBT,' he said.

NICE should say what parts of its guidance should be implemented first so PCTs can prioritise, said Dr Jenner.

David Stout, director of the NHS Confederation's PCT network, said NICE should take PCT resources into account when developing its guidance.

The guidance should also set out clearly how changes can be implemented, he said.

But Jenny Field, associate director of commissioning at NICE, insisted that following its advice could cut costs.

She said advice on long- acting reversible contraceptives could save huge sums by cutting unwanted pregnancies.

NICE public health guidance on cutting obesity and smoking can also bring savings, although it is very hard to quantify, said Ms Field.

She added that NICE had just published a guide to help PCTs use NICE guidance to commission high-quality services.