The government must reconsider the “speed and scale” of its white paper reforms, the King’s Fund has warned.

The think tank said primary care trusts and strategic health authorities should be streamlined rather than abolished.

In its formal response to the white paper consultation, the King’s Fund questioned the need to embark on a fundamental reorganisation of the NHS when it said evidence showed health outcomes and public satisfaction have improved in recent years.

It acknowledged the NHS did need some reform and welcomed giving GPs a stronger role in commissioning services, extending choice for patients and enhancing the role of local authorities in the health system.

However, it warned the scale and speed of the proposed change to commissioning would “distract attention from finding the efficiency savings needed to maintain quality and avoid cutting services, as the NHS faces the most significant financial challenge in its history”.

It identifies a number of areas, for example GP commissioning, where it believes a “more measured approach” to implementation could ensure the reforms deliver real benefits

It said GPs who are ready to take on commissioning budgets should be allowed to do so as soon as possible and their experience should act as a pilot for the rest of the country, “rather than imposing the GP consortia model in all areas of the country by 2013”.

King’s Fund chief executive Professor Chris Ham said: “There are areas where NHS performance needs to improve and we support many of the proposals in the white paper. But we question the need to embark on such a fundamental reorganisation as the NHS faces up to the biggest financial challenge in its history.

“I hope ministers will think again about the plans for implementing these proposals. This does not mean putting the brakes on across the board. In some areas, they could in fact move more quickly by beginning to test out and evaluate how key elements of the reforms will work in practice.”