Last month the DoH named the first 52 pathfinder consortia. Information from eight of England's 10 SHAs revealed GPs have grouped into around 260 consortia, suggesting there will be 300-350 nationwide.
DoH national clinical commissioning network lead Dr James Kingsland warned the figure was 'frighteningly similar' to the original number of PCTs. There were 302 PCTs before mergers in 2006 created the current set of 152.
Dr Kingsland said commissioning reforms could fail if GP consortia replicate old PCT boundaries.
Eight SHAs gave GP an estimate of how GP practices have divided up, although many said numbers could change.
The number of GP consortia is far lower than the 500-600 figure commonly cited in White Paper discussions and suggests the average group will cover around 190,000 people.
NHS Alliance chairman Dr Michael Dixon said it was likely consortia are forming either small, locally responsive groups covering around 100,000 patients or large groups covering 500,000 patients or more.
'It seems people are opting to be either small and locally responsive or large with greater financial stability.
'Hopefully people won't compromise and have sizes covering 200,000-400,000, as it achieves neither.'
But Dr Kingsland said GPs need to form smaller groups to ensure every individual practice is actively involved in commissioning decisions.
GPs are forming larger groups as worries about managing financial risk 'consume' every discussion, he said.
Dr Kingsland added he would remain 'watchful' but believed consortia numbers were likely to shift significantly by 2013, when PCTs are abolished.
The DoH response to the White Paper consultation said consortia size will 'flex rather than be fixed forever, with consortia able to expand, contract, dissolve or merge'.
The NHS Operating Framework also revealed consortia are likely to inherit debts PCTs accrue from 2011/12 onwards.
- See our map of GP pathfinder consortia
- Editor's blog: How many GP commissioning consortia there will be and what their biggest challenge is