The Association of College Registrars and Administrators questioned 291 clerks and found 28 without an approved job description, while a further 14 were unsure whether theirs had been cleared by their corporations.
The association's chairman, Robin Jones, clerk at Waltham Forest College in north-east London, was concerned by the finding.
He urged clerks to get a fully approved job description as soon as possible, setting out their responsibility to report directly to the chair of governors, as well as their role in advising all governors and dealing with issues, such as whistle-blowing.
"Colleges must be clear about exactly what their clerk should do," he said. "They are a major point of contact."
The survey also found that more than two-thirds of clerks (208) combine their role with other college work. Most of thee (166) are employed at senior management level. Just 19 were self-employed while 10 were employed by third parties paid by a college.
"We are not surprised that so many clerks have other roles," said Mr Jones. "It's a strength that the clerk is in the best possible position to assess the corporation's needs."
ACRA also discovered more than half of clerks (161) had been in their present post for less than four years. Nearly one quarter (67) were contracted to work as clerks less than 10 hours a week ,while 13 spent more than 25 hours per week on clerking duties.
Levels of administrative support varied considerably. While 85 had their own personal assistant and a further 131 shared a secretary or PA, the remaining 75 had no dedicated support staff. "There are people who are left totally to their own devices," said Mr Jones.
The survey is likely to be discussed at the inaugural conference for clerks, organised by the Further Education Funding Council at the Queen Elizabeth II Conference Centre in London on April 13.