Commission chief executive Anna Walker said that as primary care trust budgets increase, the public has a right to see where its money is going.
Speaking at a conference this week, she said: 'Commissioners need a stronger understanding of the needs of their populations.
'To help this happen, we must put in place a mechanism for holding people publicly accountable. We believe we need an independent assessment of commissioning.'
The message came after Mr Brown confirmed there would be a health and social care bill as part of his legislative programme for the next year. This will establish a new regulator, Ofcare, which will be formed in 2008 from a merger of the Healthcare Commission, the Commission for Social Care Inspection and the Mental Health Act Commission.
As revealed by HSJ, underperforming trusts will face fines and closure under powers given to Ofcare (see 'Leak reveals plan for Ofcare regime of fines and closures').
In a Commons statement, Mr Brown said: 'The Health and Social Care Bill will create a stronger health and social care regulator, with a clear remit to ensure improved access, clean and safe services and high-quality care.'
Ms Walker proposed that Ofcare carries out independent assessments of commissioners, which she said were supported within the NHS.
But NHS Confederation PCT network director David Stout said there was a danger that a PCT could be regulated, performance assessed, or performance managed three times over by strategic health authorities, Ofcare and the Audit Commission.
'It takes an awful lot of time to go through the processes,' he said.
However, he said there needed to 'be some form of accountability of commissioners. The way it works at the moment is not particularly satisfactory'.
SHAs, rather than regulators, could take on independent assessments as long as there was a central model for how this could be carried out, he said.