Labour has launched a scathing attack on the Government's wide-ranging health reforms, branding them a "mess" and a "catalogue of compromises".
Health spokeswoman Baroness Thornton hit out at the proposed changes as peers began an extended sitting on the Health and Social Care Bill.
The Lords was forced to sit more than three hours earlier than usual in a bid to complete the Bill's marathon committee stage by the Christmas recess next week. As day 12 of debate got under way, Lady Thornton focused on the role of the independent regulator for all healthcare services, Monitor.
"The Bill is a mess. It is a sad catalogue of compromises," she said. "We believe that Monitor is being asked to fulfil too many functions, set too many priorities, some of which are potentially in conflict with each other."
Lady Thornton called for the section of the Bill dealing with Monitor to be rewritten to make it "simpler and more coherent".
Labour had introduced independent regulation of quality into the NHS. But it did not accept "the handing over of economic regulation of the NHS to a quango".
She told the House: "There is a place for competition. It is not, and never can be, the main driving force for reform of the NHS. We are against promotion of competition for its own sake as this Bill originally intended.
"We believe the balance between co-operation and competition is a matter for the Health Secretary to determine in the best interests of patients, not for a quango to determine in the interests of some ideological bias."
Health minister Earl Howe said the section of the Bill dealing with Monitor was "much misunderstood" but "fundamental" to NHS modernisation. He said: "We need to improve health outcomes and increase productivity in the NHS."
This part of the Bill helped enable this to happen by "establishing a clear and comprehensive legal framework for sector regulation to protect patients' interests based on the principles and values enshrined in the NHS constitution".