Mr Cameron was speaking on Monday at the Vitality Partnership group of practices in Birmingham which is providing evening and weekend access as part of the prime minister's Challenge Fund.
Dr Nikita Kanani, honorary secretary of the National Association of Primary Care (NAPC), said: 'The NAPC is working with members around demonstrating and implementation of the Five Year Forward View around new models of care. We have spoken with numerous members that are doing extraordinary things in their communities and are already providing seven-day access and beyond.'
RCGP chairwoman Dr Maureen Baker said: 'We manage 90% of patient contacts in the NHS, but as patient demand has rocketed and our workloads have become more complex, the share of the NHS budget for general practice has fallen to an all-time low of just over 8% in England.
'We welcome the government's commitment to delivering the Five Year Forward View and hope that it will honour its promise of 5,000 additional GPs as a matter of urgency.'
Labour London Assembly health spokesman Dr Onkar Sahota said: 'I'd like to see surgeries properly staffed and open seven days a week but it's concerning that the health secretary makes no mention of how he will deliver his pledge.
'In London we have a GP crisis on our hands, with our practices overstretched and too few doctors available to deliver care to our aging and expanding population. Adding more duties to an already overburdened workforce, without making it clear how this will be resourced, is not going to result in better care for patients.'