Council leaders have attacked proposals by NHS London to merge primary care trust commissioning functions in the capital.
London Councils, which represents London's 33 boroughs, claims a policy being developed by the strategic health authority and London PCTs to enable PCTs to make commissioning decisions in groups may make it harder for trusts and local authorities to work jointly.
Chair Merrick Cockell (Con) said: "We recognise the importance of strengthening commissioning arrangements across London - particularly around acute care. But the fundamental link between a borough and its local PCT is vital.
"Our communities would not accept mergers or dramatic changes to operational structures that were introduced without proper consultation with local councils - their elected representatives."
HSJ understands council leaders have become concerned the move will make succeeding in new comprehensive area assessments harder, following a meeting last week where the proposals were outlined by SHA chief executive Ruth Carnall.
Council leaders also called for a debate over increasing collaboration in public health with local government, further integration of specialist services such as children and mental health, joint working to "support GP services locally" and the opportunity to "work more productively with PCTs on wider issues such as health inequalities and combating deprivation".
An NHS London spokesman dismissed concerns that commissioning groups would harm working relationships between councils and PCTs.
"I don't think in reality it would," he said. "It would just mean that one area was working with three or four local authorities in a lot of cases. The PCT will still exist - it's not merging PCTs as such."
He added that many local authorities work together in some areas and if PCTs were to demerge commissioning and providing functions, it made sense to strengthen the commissioning side of their role.
HSJ's Building Effective Partnerships conference is in Birmingham on 16 September