The charity said proposals within the Health Bill could undermine the integration of services across primary and secondary care.
It said it had concerns that the proposed structural reform, with different aspects of diabetes care commissioned by a range of commissioners, could further fragment how services are provided.
Failure to integrate services can lead to a range of problems, the charity said. These include duplication of tests, which can delay care, inconsistency in advice and patients having to repeatedly provide the same information to different parts of the system.
Diabetes UK set out its concerns in written evidence to the House of Commons public bill committee, which is reviewing clauses in the Health Bill.
The charity said a patient-centred NHS required integrated care in which a person with diabetes has access to the multidisciplinary skills of generalists, specialists, allied health and other professionals in a timely and co-ordinated manner.
The evidence it submitted acknowledges there are requirements in the Bill for integrated and partnership working. But the charity said it questioned the strength of these duties and the degree of accountability within the new system to ensure this occurs.
It said it believes the duties to encourage partnership working placed on the NHS Commissioning Board and Health and Wellbeing Boards should be strengthened to ensure this occurs.
RCGP clinical lead for diabetes Dr Brian Karet said that the issue of service integration needed to be 'positively addressed' as consortia develop.
'The GP consortia that are forming are just that,' he said. 'They are not inclusive at all. They don't include primary care nurses and don't include links with secondary care. GPs need to set up very early links with secondary care colleagues. Unless we can embed fully integrated care there is a risk that care will become fragmented.'