Dr John Diamond, who has written to heath minister Mike Nesbitt, told the BBC GPs were at their ‘wits end' and angry about underfunding and unsafe workloads.
Dr Diamond said: ‘I would argue that if you compare the funding that we get in our region compared to others in these islands, we are very much the poor relation by a long way.'
The comments came after GPs overwhelmingly rejected a £9.5m contract offer.
A Department of Health (DoH) spokesperson said it was a ‘matter of regret' that GPs had rejected the 2025/26 GMS contract.
The DoH said £414m had been invested in services this year, including pay uplifts and investments in multi-disciplinary teams to expand capacity. A further £2.9m has been invested in GP elective care.
Minister Nesbitt also repeated his intention to implement the DDRB 2025/26 recommendations in full, entailing a further £11.5m investment but added the £9.5m contract was the ‘best and final offer for 2025/26'.
The DoH spokesperson added: ‘The Department and minister remain committed to the principle that GP services should remain free to all patients at the point of access and do not agree that the privatisation is the way forward for GPs.'