Managers and GPs have warned that further 'wholesale reorganisation' and job losses could follow if dozens of primary care groups decide to move towards trust status in 1999.
Shadow PCGs wanting to become primary care trusts in 2000 had until the end of January to express a formal interest to health authorities.
Commentators predict that 50 to 60 PCGs could become PCTs in the first year - a figure supported by HSJ inquiries into how many PCGs have raised the issue with HAs.
Regional offices predicted that between six and 15 PCGs in their areas would signal readiness to become PCTs.
And at least three HAs are expecting expressions of interest from all their PCGs.
North Nottinghamshire HA has a history of locality commissioning as does Newcastle and North Tyneside HA. All nine PCGs in the two areas are keen to move forward to PCT status.
East Riding HA is also expecting all four of its PCGs to express an interest in trust status.
Shadow PCGs are only now appointing chief executives and management teams. But there are already warnings that PCG staff should be ready for change.
NHS Confederation associate director of health policy Cathy Hamlyn said there was 'conflicting information' about the number of future PCTs, but she expected fewer than 60 in the first year.
She said the effect of 'structural change' on managers' jobs was a concern for PCG staff, and also 'for community trusts which will be directly affected by the move to PCTs'.
'Unless it is very carefully planned, this all has the potential for disruption without achieving the outcomes that PCGS were devised to produce, ' she said.
Michael Sobanja, chief officer of the NHS Primary Care Group Alliance, said: 'I have heard figures for year one of between 50 and 80 PCTs', and acknowledged this would affect the management teams of the PCGs involved.
But he also argued that setting up 481 PCGs across England had resulted in 'some fairly rough and ready' groups that might not be able to cope with risk management arrangements, demand management and primary care development plans.
There was 'more danger' to managers' jobs from mergers than from moving up the levels towards trust status, he said.
Asked how many PCGs were thought to have expressed an interest in PCT status, responses from regional offices ranged from 'a handful' to 'about 15'.
South East regional office, covering the home counties from Kent to Oxfordshire, expected between six and 10 expressions of interest in PCT status.
A spokesperson for Eastern regional office said 'five or six' PCGs were 'very keen' on trust status. But more would 'throw their hats in the ring' to keep their options open for the first full year of PCG operation.
Graham Rich, director of commissioning for Newcastle and North Tyneside HA, welcomed the high level of interest in PCT status in the area.
He said this was because the groups 'were already thinking in terms of 1999-2000' and wanted 'to keep their options open for trust status in advance of the guidance'.