The guidance contrasts with health secretary Andy Burnham's announcement last year that the NHS should be the "preferred provider" of NHS services.
Chief executives body Acevo, which has been campaigning for a reversal of Burnham's position, hailed the guidance as "the final nail in the coffin of the preferred provider policy".
A statement issued yesterday by Burnham said: "Where existing NHS services are delivering a good standard of care for patients, there is no need to look to the market.
"Independent and third sector organisations will continue to make a valued contribution to providing treatment and care.
"Where primary care trusts are commissioning new services we expect them to engage with a range of potential providers before deciding whether to issue an open tender. These decisions will be made locally and we will not choose to exclude either NHS or private providers."
The department's guidance comes in three documents: Principles and Rules of Cooperation and Competition, PCT Procurement Guide for Health Services and Commercial Skills for the NHS.
The revised Principles and Rules of Cooperation and Competition says "commissioning and procurement must be transparent and non-discriminatory". It contains no reference to preferred providers.
The PCT Procurement Guide for Health Services says "the commissioning process, including any form of procurement, should be non-discriminatory and transparent at all times, including neither favouring nor excluding any particular provider.
"The procurement process should not give an advantage to any sector (public, private, third sector/social enterprise)," it says.
Commercial Skills for the NHS says "where services are tendered, competition will be fair, open and non-discriminatory".
Stephen Bubb, chief executive of Acevo, said: "This guidance is the final nail in the coffin of the preferred provider policy, which has been well and truly neutered.
"It sends out a totally clear message to NHS commissioners: do not treat the NHS as preferred provider, but rather treat all sectors equally.
"I am pleased that this distraction is now over, and that we can concentrate on getting the best services for NHS patients."