Some GPs are earning as much as £250,000 a year after expenses due to a new GP contract, the BBC has been told.
GP wages have risen by up to 25% since the contracts were introduced in 2004, according to specialist accounts.
The figures come from an annual survey by the Association of Independent Specialist Medical Accountants due out later this month.
Experts have said the contract was ill devised and is partly responsible for current NHS deficits.
The average earning of a GP is now believed to exceed £100,000. But the figures also give evidence that some GPs are earning up to £250,000.
Policy experts have said the government miscalculated its sums when it negotiated the deal. The Department of Health has confirmed the current overspend on GPs is £300m.
However, Dr Hamish Meldrum, lead GP negotiator for the British Medical Assocation, told the BBC that some GPs were earning more money because they were now running a complex business.