NHS Alliance chairman Dr Michael Dixon warned that primary care was developing 'without a plan' in parts of England, and could be left open to private-sector takeovers.
The manifesto is likely to be published in March, as CCGs prepare to take over from PCTs, and could offer suggestions on how the GP contract can cut bureaucracy for practices.
Dr Dixon told GP: 'It's going to be timed for the beginning of CCGs. It is some thoughts from front-line clinicians, managers and think-tank academics about what primary care may look like in the future.'
Dr Dixon said CCGs needed more power to direct funding at priorities identified by patients and local GPs. He said GPs wanted to expand services but funding was not available.
'The NHS Commissioning Board will hold GP contracts - but that may be increasingly just a core contract.
'The current GP contract is worth £7bn; if a bit of that is handed to CCGs, fine, but the £60bn CCGs will also have is the bit that matters. We need to look at how we can put some of that into general practice.'
Dr Dixon said 'endless roadblocks' had prevented primary care from developing and taking on work from hospitals, and the manifesto would look at how to tackle this.
'We need to make sure we get that move of resource into primary care, maybe through looser, lighter commissioning mechanisms.
'We'll be looking at the GP contract itself as part of that. One thing's blindingly obvious: it's not perfect. Although the QOF has brought improvement, GPs feel very constrained. One of our aims is to try to take the bureaucratic load off general practice and allow it to do what it does best - use its knowledge of local priorities that matter to patients.'
Dr Dixon warned that in parts of England, practices were forming federations, 'sometimes as collectives or social enterprises'.
'If they develop more services, that's good, but there are dangers. Those same conglomerations may look highly attractive to private industry.'
He said NHS leaders were too busy with structural reform to focus on primary care: 'I don't think there's a grand plan in terms of what primary care looks like in the future. This is us saying front-line clinicians and patients must have a say.'