Peers have urged the government to delay the establishment of the new health and social care regulator, warning that the body will be 'weakened by compromise'.

The Care Quality Commission is set to replace the Healthcare Commission, Commission for Social Care Inspection and Mental Health Act Commission in 2009.

During a House of Lords debate on the Health and Social Care Bill last week, cross-bench peer Lord Ramsbotham, who successfully defeated the planned merger of five justice watchdogs in 2006, expressed grave concerns about the plans. He said: "If you bring three specialist organisations together... each will be weakened by trying to compromise."

Labour peer Lord Lipsey said: "We should leave it longer before deciding that the present system cannot be made to work."

But health minister Lord Darzi said, given all the preparation done so far for the CQC, a delay was not practical and could lead to "confusion" and "loss of momentum".

However, in a boost for campaigners who want the role of the regulator to be clarified, Lord Darzi promised changes to the clause that sets out the commission's functions. Amendments including giving the regulator a duty to "protect and promote the interests of people who use health and social care services" were "worth exploring", he said.

Don Redding, head of policy at the Picker Institute - which along with Which? and the National Consumer Council has lobbied for such a duty - welcomed Lord Darzi's moves to redraft the clause.