Thirty per cent have been asked to carry out quality framework-related work for which they had no formal training.
Ten per cent of nurses employed in practices said they would not refuse to carry out quality framework tasks even if they had not been trained, the survey found.
The GPC has urged nurses to tell GPs they need training if they are asked to carry out work they are unsure about.
Dr Richard Vautrey, GPC deputy chairman, said: 'Nurses need to recognise that they are responsible if they act beyond their competencies. It is in their own interest to protect themselves by not doing work they are not trained to.'
'There will always be a tension between employer and employee about training and what is needed', he added.
Senior nurses said the findings were 'appalling' and warned that staff working beyond their competence could be struck off.
Nurses reported being asked to carry out COPD, asthma, depression or other reviews without training. Some said their practice had arranged training when they voiced concerns.
Others said they had been refused time off for training and had been forced to do it in their own time.
Fifty-four per cent of practice nurses said their practice had not reinvested quality framework profits in improving services since it was introduced in 2004.
Regarding the high number of nurses who said that quality framework money was not being ploughed back into improving services, Dr Vautrey said: 'It is not a case of looking at quality money, enhanced service money or MPIG money in isolation.
'The practice gets one set of money and invests that in the practice.'