Practices in Tower Hamlets in east London will be ranked A, B or C on indicators that in some cases go beyond the requirements of their contract.
A spokesman for Tower Hamlets PCT confirmed that practices will need to offer extended hours to be A-banded on access, a priority area for the scorecard.
The guidelines for the scorecard, set to be rolled out in April, allow for C-banded practices to be served remedial notices. Critics fear that such practices could be vulnerable to takeover by an alternative provider.
GPC negotiator Dr Stewart Drage said he was concerned about a domino effect, with PCTs around the country following Tower Hamlets.