The number of complaints made against GPs has increased by 11% in a year, according to figures.
Written complaints were made against 48,597 NHS GPs and dentists in England in 2008/9, compared to 43,942 in 2007/8, figures from the NHS Information Centre showed.
Complaints have risen 28% since the Labour government came into power in 1997/98.
However, a number of GP surgeries have said that it is their efforts to inform patients of their right to complain that has driven the figures upwards, while the Department of Health said the data was not representative of the whole NHS.
A spokesman from the department said: "All patients deserve the highest quality of care from the NHS, where care falls below expected standards, this can be distressing for the patients concerned and their families and we expect trusts to take immediate action to investigate and ensure this does not happen again."
Critics say the contract has given GPs a hefty pay rise while surgeries have at the same time cut back on their evening and weekend services.