Dr Rowan Brannigan, a member of Southern LMC, said practices lost between £5,000 and £50,000 as a result of cuts to GMS funding. He warned that many practices have had to stop carrying out minor surgery, travel vaccinations and contraception services.
Practices have also been forced to change surgery opening times, and have been unable to provide cover for maternity or staff leave as a result of the loss of funding, he said.
Dr Brannigan said: 'This is a worrying development and doesn't make sense in terms of the care provided to patients.'
Northern LMC member Dr Pamela Logue said her practice has lost £30,000 as a result of the loss of funding.
'That's a huge amount of money out of a small, four-man practice and it meant we didn't replace a member of staff,' she said.
Northern Ireland GPC chairman Dr Brian Dunn said the cut in GMS funding reflected 'a lack of imagination and understanding by civil servants'.
A motion condemning the 'discriminatory defunding of GMS services' was passed unanimously by the conference.