The announcement was made as a report by NHS leaders warned that the "extraordinarily risky" reforms may fail if they are not enthusiastically embraced by GPs.
The NHS Confederation paper described Health Secretary Andrew Lansley's plan to hand GPs in England the power to commission 80 billion of treatment for patients – 80 per cent of the entire health service budget – as "undoubtedly the biggest shake-up of the NHS in its history".
Unless large numbers of GPs get actively engage in the strategic challenges of changing their local health services, there was a danger of "potentially overwhelming" pressures leading to "widespread financial problems... sub-optimal performance and longer waiting times", it warned.
In a speech today, Prime Minister David Cameron will announce that a further 89 GP groups serving 28.6 million people have put themselves forward as "pathfinders" to pilot the new arrangements, bringing the total number of consortia to 141.
Shadow Health Secretary John Healey said the NHS Confederation report was a "big red warning light" of the dangers of the reorganisation plans, which he described as "a cocktail of instability and uncertainty laced with broken promises".
The paper reports the conclusions of a summit of healthcare managers, doctors' leaders, patients groups and policy experts who discussed Mr Lansley's proposals.
Those taking part agreed that the reforms could produce "some very beneficial effects for patients and population health", but warned that implementing the changes at a time when management resources were being cut by 45 per cent and the NHS as a whole was facing its toughest financial climate for many years was "extraordinarily risky".
But Mr Lansley said the rapid take-up of pathfinder status showed that GPs were keen to take on the new responsibilities and added that the changes would enable them to make the decisions that better met the needs of their local communities and improve outcomes for their patients.