Practices will need to generate data to show how they use NHS resources as GP commissioning takes off.
David Stout, chairman of the NHS Confederation's primary care network, said this is likely to be funded by reallocating money from elsewhere in the contract, such as the QOF.
'If GPs are looking for incentives to deliver commissioning it is unlikely there will be more money in the system,' he said.
Details of how to reallocate QOF money would have to be negotiated between the GPC and NHS Employers.
But contract negotiations have stalled as the DoH awaits results of the White Paper consultation, which ends this month, and a Treasury spending review.
GPC deputy chairman Dr Richard Vautrey said negotiations were stuck in 'preliminary talks' as NHS Employers negotiators awaited clear instructions from the DoH.
'NHS Employers haven't been given a mandate by the DoH yet,' he said. 'Talks have been delayed for a whole variety of reasons. There's the consultation period, it's conference season, and there is the Treasury (spending) review. There are lots of bits of the jigsaw that need to be in place before we can start.'
Dr David Jenner, GMS/PMS lead at the NHS Alliance, said taking money out of the contract and suggesting GPs earn it back through commissioning would be 'unacceptable' to most GPs.
'I think people suggesting GPs can earn back money through what might be quite a lot of work are out of touch,' said Dr Jenner.
He predicted the GMS contract would change 'very little' this year as GP commissioning plans remained undefined. 'There is neither the time or the opportunity this year for major changes,' he said.
The National Association of Primary Care (NAPC) revealed this week it would call for a 'significant amount' of practice income to be at stake for GPs who do not commission.
Meanwhile, NHS reforms may face delays after the union Unison was granted the right to take legal action against health secretary Andrew Lansley.
The union claims reforms started without adequate consultation.