Public access to information may be “increasingly restricted” because NHS reforms could increase the involvement of independent providers, campaigners have warned.

The Campaign for Freedom of Information has written to health secretary Andrew Lansley raising concerns about how the public will be able to scrutinise the health service if the reforms are implemented.

The letter, from the campaign’s director Maurice Frankel, claims some information about independent sector healthcare providers will not be accessible.

It said this “may distort the competitive process” with NHS providers, which are subject to Freedom of Information Act rules.

The campaign’s letter said although some information about private providers may be requested under the act if it is held by commissioners, “we are concerned about what is not covered by these provisions”.

For example, wrote Mr Frankel, standard NHS contracts do not contain “any direct requirement for the provider to hold records about or report on the quality of the services environment (ie, the premises and facilities) or the equipment used in the treatment of patients”.

The letter also said “there appears to be no specific reference” in contracts to a requirement on providers to supply commissioning bodies with the types of information an NHS body can be asked to provide.

It said: “This would represent a major loss of existing information rights. As treatment previously provided by NHS bodies is increasingly carried out by independent providers, the existing broad FOI right will be replaced by narrower duties to provide or report on specified information only.

“The right to enquire in depth into new issues as they arise may disappear altogether. We hope the government will not permit this to happen.”

A Department of Health spokesman said: “It is wrong to say that the bill will curtail access to data. The bill does exactly the opposite… [It] amends the Freedom of Information Act to ensure it applies to the NHS Commissioning Board and clinical commissioning groups.”