NHS London's strategic plan for 2010-2015 orders PCTs to monitor how long GPs spend in direct contact with patients and to boost the proportion of appointments tackled by nurses from 33 per cent to 50 per cent.
But Dr Michelle Drage, chief executive of Londonwide LMCs, said practices have the right to withhold data and refuse work outside the GMS or PMS contract.
'A practice defines how long it spends with patients. If they (NHS London) had their way, there would be someone from (management consultants) McKinsey in there with a clip-board counting the seconds,' Dr Drage said.
'Practices need to function as businesses and count to 10 before they part with any kind of information that the PCT can use (for performance management). They should think about if it is in their best interests.'
Delivering Healthcare for London: Strategic Plan 2010-2015 sets out plans to increase GP productivity as work is transferred out of hospitals.
It suggests upping the time GPs and nurses spend with patients: 'GPs spend 18.5 hours of their contracted 37.5 per week on direct patient-facing care. The plan is to move to 25 hours per week, a 35 per cent increase.'
Balanced scorecards will also monitor individual GPs' performance and PCTs will 'use primary care indicators to look at best practice in use of staff'.
Cutting appointment times could save £570 million, according to the document.
The plan says local enhanced services (LESs) will pay practices to take on extra work from hospitals.
Dr Drage said: 'If they use the money they currently spend in hospitals on a long-term condition and reallocate it to GPs, we are all for it. If they are saying we will keep the savings and give you some token LES payment, then that won't do.'