They could also become permanent structures that undermine GP consortia control over commissioning of services, the Alliance warned.
A survey of its network of PCT non-executive directors revealed fears that efforts to re-shape PCTs into clusters will mean they have little time left to support the development of GP consortia. They will also be too focused on savings to support local needs, the network warned.
One respondent to the survey said: 'The driver for clustering is sharp reduction in management costs available to PCTs.
Efficiencies in running costs will come at the expense of sensitivity to local circumstances.'
Another respondent said: 'The most likely consequence of this will be a loss of local focus which is particularly important when it comes to patient safety and service quality.'
One member of the network said PCT clusters were rapidly becoming powerful organisations, and that GP consortia may find it hard to wield influence over them.
'Clusters are supposed to be only a transition arrangement, but these things have a way of becoming permanent.
'Already there are clear signs of aggregating power upwards and this will be very hard to unlock as the new GP consortia come on stream. Local citizens are being ignored entirely and the remoteness of the sector to borough activity will be damaging,' the respondent to the survey warned.