Private medical care providers may be forced to respond to Freedom of Information requests.
An Early Day motion, signed by 34 Members of parliament, notes that £7bn worth of contracts are up for tender to the private sector and the change in the law would level the playing field with the NHS.
Grahame Morris, MP for Easington (Lab), said there was a "growing scandal of the procurement model that favours the private health sector over the NHS", adding that hiding behind commercial confidentiality compromises "the best practice aspirations of the public sector".
The motion demands: "all private healthcare companies be subject to freedom of information requests under the terms of the Freedom of Information Act 2000 in the same way as existing NHS public sector organisations".
Shadow justice secretary Sadiq Khan said a Labour government would ensure FoI covered the "delivery of public services by private companies". This would include prisons, schools and the health service.