Senior DH figures said it was 'essential' that patients are prescribed sufficient self-blood glucose measurement test strips amid rising cases of ketoacidosis.
Anecdotal reports from the charity Diabetes UK and others suggest some patients are being 'refused' prescriptions for the strips, officials said.
The warning came in a letter signed by officials including Dr Rowan Hillson, national clinical director for diabetes. It follows an all-party parliamentary group meeting with health minister Anna Soubry.
'While testing strips dispensed in primary care may appear to have a premium cost, the wider costs to the patient’s quality of life, their safety and ability to work and to the NHS of complications of uncontrolled diabetes far outweigh these costs,' the letter reads.
'GPs and pharmacists should work collaboratively with patients to ensure the optimal amount of testing strips are prescribed and supplied to type 1 diabetics. Too few can lead to serious clinical consequences. Too many can lead to wastage.'
There were 8,472 cases of ketoacidosis in England and Wales in 2010/11 and experts say the figure is rising.