Just 6% of respondents to a poll of more than 1,000 GPs by researchers from the Warwick Medical School said they planned to increase their hours over the next five years.
The researchers called for 'urgent action' to prevent a deepening workforce crisis in general practice.
Of 1,192 GPs who took part, 978 planned to leave general practice, take a career break or reduce their working hours in the next five years. Of these, 488 planned to quit practice altogether, while 279 planned a career break.
Seven-day GP service
Key factors influencing GPs to quit or cut back hours were plans for a seven-day GP service, intensity of workload, volume of workload, job satisfaction and time spent on unimportant tasks.
Some GPs in the study, published in the journal BMC Family Practice also highlighted age and changes to pension rules.
The findings highlight the growing crisis in the profession. GPonline reported last week that pressure on GPs has sparked an exodus from partnership roles to locum work.
BMA leaders have called for an end to the 'scandalous' waste of 14m GP appointments a year through unnecessary demands for practices to re-refer patients who miss hospital appointments.
The government has pledged to deliver an extra 5,000 GPs by 2020 to bolster the primary care workforce. A DH spokeswoman said last week: 'We will deliver an estimated 5,000 more doctors in general practice by 2020 as part of a 10,000-strong boost to primary and community care staff.
'GPs tell us these other health care workers are invaluable; reducing pressure and freeing them up to spend more time with patients.'