Summary care records, which contain key medical information that can be accessed wherever patients receive treatment, are being rolled out across the capital by the local SHA, NHS London.
Patients have been advised by PCTs to 'inform their GP' if they wish to opt out of the scheme.
However, Londonwide LMC highlighted that there is no money available to support practices during the roll-out of summary care records.
GPC negotiator Dr Chaand Nagpaul said GPs would 'rightly expect' to be properly resourced for taking part.
'The GPC believes that for a practice to participate in the programme will undoubtedly require additional workload through meetings to develop practice policy around the process, as well as consent issues that may fall upon GPs to explain to patients,' he said.
'LMCs, on behalf of GPs, should ensure that practices do not incur unresourced work in being part of the programme.'
A spokeswoman for Londonwide LMCs said it would raise concerns about workload with PCTs.
NHS London was not available for comment.