Academics are spending the equivalent of an extra ten-person seminar a week on unscheduled contact with students.
Hepi's survey of 15,000 students has revealed the extent of students' demands on staff outside timetabled hours for the first time. The average level of unscheduled contact with academics is 1.8 contacts per term - "quite substantial", according to Hepi's report.
"Assuming a ten-week term, this equates to 0.2 contacts per week. If each contact lasted half an hour and is on a one-to-one basis, this is equivalent in terms of staff time to an additional ten-person seminar each week," it says.
The authors suggest that there is a minority of students for whom unscheduled contact adds "very substantially" to the amount of time spent on them by staff.
"This potentially raises issues of equity - it may be that a minority of more assertive students are gaining a considerable advantage through this form of informal tuition," the report suggests.
Catherine Kaiserman, a language teaching fellow at Leeds University's department of French, said: "Students are always asking for more contact hours, which, of course, we cannot give. University education is a limited number of contact hours and then private study, which they sometimes don't understand."
Rupert Hildyard, English programme leader in the department of humanities at Lincoln University, said e'mail could also be a way of students making unscheduled contact with their tutors.
"We ask our students to exercise judgment in contacting staff by e'mail... and whether there might be more appropriate ways of getting information," he said.
Sally Hunt, general secretary of the University and College Union, said: "Increasing student numbers has inevitably added to lecturers' workloads. The crucial pastoral care that they provide, alongside academic advice, can often be the difference between students dropping out or persevering."
"This extra commitment, coupled with an admin overload, contributes to lecturers consistently being named as one of the professions putting in the most unpaid overtime each week," she said.
Students seek good teachers
More training for academics is high on the list of student priorities, the Hepi survey indicates.
Asked what they wanted to have the extra money from the new student fees spent on, reducing fee levels was students' top priority, followed by better financial support for hard-up students.
But providing better learning facilities and better training for lecturers were thought the next most important.
"Students rated training for lecturers more highly than smaller teaching groups, suggesting that it is the quality of the teacher that concerns students more than the character of the teaching occasion," says the Hepi report.
Graham Gibbs, former director of the Oxford Learning Institute, described the finding as "striking".
"New teachers who experience an extended teaching development programme receive significantly improved student ratings. However, such training is now almost universal for new academics in the UK, and compulsory at some institutions. So the problem may lie either with less effective training or with students' overall experience being dominated by older academics who took up their posts before training was available or required," he said.