NHS Stoke-on-Trent has devolved 80% of its budget to the local GP consortium.
NHS Alliance GMS/PMS lead Dr David Jenner said that he expected consortia - often operating as PCT subcommittees - to handle up to '65 to 70%' of PCT budgets.
This money is likely to cover 'the payment by results budget, prescribing budget and in some cases the community health budget', Dr Jenner said.
But in some areas consortia have taken on smaller budgets. Bolton Health Consortium controls £113 million, 23% of NHS Bolton's budget.
Chief executive of Berkshire, Buckinghamshire and Oxfordshire LMC, Dr Paul Roblin, said that for consortia in his area, '30 to 40% is the commonest figure'.
Wessex LMCs chief executive, Dr Nigel Watson, expected local consortia to take on around 25% of PCT budgets.
GPC negotiator Dr Chaand Nagpaul said PCTs were likely to ask consortia to 'focus on the Quality, Innovation, Productivity and Prevention (QIPP) agenda and enable productivity gains'.
Consortia set up as PCT sub-committees can make funding decisions, but accountability will ultimately remain with the PCT, Dr Roblin said. 'There will always be some oversight from the PCT,' he said.
NHS Confederation PCT Network director David Stout said that, to deal with potential problems such as overspends, PCTs must set up a 'very clear' scheme of delegation.
He said it was likely that PCTs would maintain the power to revoke budgets if the arrangement did not work. 'PCTs have a statutory duty to break even,' Mr Stout said.
Dr Watson warned consortia taking on budget responsibilities to be aware that they may be legally liable for their actions.
Recent guidance from Londonwide LMCs advised consortia to gain confirmation that they were covered by PCT statutory indemnity.