The National Primary Care Research and Development Centre (NPCRDC) surveyed patients at 42 practices over a two-year period.
Researchers found that few patients volunteered an opinion on Saturday surgeries, but when specifically asked, 30 per cent said it was a problem.
Twenty-two per cent said they would like surgeries to hold evening clinics - again, only when pushed on the point.
Although the research was completed in 2005, NPCRDC director, Professor Martin Roland said the trend found is likely to have continued.
He said: 'We have only used samples of patients, but we think they are a fair representation of the majority.
'The vast majority of patients are happy with the care they receive - we carried out this study in 1998 and satisfaction has steadily increased since then. But, access issues are still a concern for a considerable number of people, particularly for some ethnic minority groups.'
The study, which found the number of patients rating their GP as good or excellent increased by 9 per cent to 70 per cent between 1998 and 2003, paints a different picture to figures published by the government.
A DoH access survey published in July found only 14 per cent of patients are unhappy with their surgery's opening hours. Just 4 per cent called for evening opening hours.
Professor Roland said: 'It is true that we had to prompt patients, but perhaps they accept some problems with service because they are so used to them they don't think about complaining. Or perhaps they do not see it as a high-priority issue.
'These are complex issues and we have submitted our findings to the government.'
Although funded by the government, NPCRDC is an independent research body comprising academics from Manchester and York Universities.
GPC deputy chairman Dr Richard Vautrey said: 'If you ask people if they would like it to be Christmas every day they would probably say "yes", but the NHS has finite resources. A better question would be to ask what their priority would be, their answer would be very different.
Would they want to get the extra hours at the expense of what they now take for granted as part of the care they receive?
'Politicians can promise everything, but there is a firstname.lastname@example.org