Details of GMS contract changes for 2013/14 have been finalised in England, Wales and Scotland, but the Northern Ireland health department has yet to confirm the changes it plans to impose.
Northern Ireland GPC chairman Dr Tom Black said that if the government presses ahead with tough GMS contract changes - believed to be the harshest in the UK - GPs will withdraw support for wider reforms.
NHS reform plans launched this week by Northern Ireland health minister Edwin Poots, dubbed Transforming Your Care (TYC), aim to move more work into the community through 'a focus on prevention, earlier interventions, integrated care and promotion of personalised care'.
Dr Black said GPs had supported the reforms 'from the start'. He said: 'We strongly believe this is what our local health service needs.'
But he added: 'TYC represents a huge shift of work from hospitals to general practice, which must be planned, agreed and resourced. We have yet to see the detail as to how this will proceed.
'In the midst of this, minister Poots plans to impose a new contract on GPs the same day as the start of TYC on 1 April 2013.'
Dr Black said the contract proposals outlined by the Northern Ireland government had not been 'negotiated or agreed by GPs' and were the 'harshest seen in the last 30 years'.
'There will be a huge increase in workload and a real cut in resources that will regrettably lead to practices having to make staff redundant and reduce essential patient services,' he warned.
'GPs are very concerned about the impact on patient care, including access to services, increased prescribing, increased dependence on secondary care, and a huge increased focus on targets and box-ticking, rather than dealing with the patient as a person.
He added: 'Health ministers in Scotland and Wales have already reached agreement with their GPs on contract changes. We need Mr Poots to meet with GPs and agree a contract that will allow them to engage with TYC.
'A failure to reach agreement will result in GPs being unable to engage with TYC at any level at this time.'