Speaking at a conference on education and social mobility, Richard Harvey, director of admissions and outreach at the University of East Anglia, said statements from the Independent Taskforce on Student Finance Information were likely to put off many prospective students from low-income backgrounds.
The task force was launched in June to "tackle myths and misunderstandings" about the costs of university when tuition fees rise to up to ?9,000 a year next autumn.
It is headed by the personal finance guru Martin Lewis, founder of MoneySavingExpert.com, and includes representatives from the National Union of Students and Universities UK.
But Dr Harvey told the conference in London last week that the task force's guidance on debt repayment would actually exacerbate the fears of many.
His criticisms centred on Mr Lewis' advice that some graduates will be better off under the new system, as they will face lower repayments during their working life before the remainder of the debt is eventually written off after 30 years.
"We are employing Martin Lewis to say [to students], 'Do not worry because the loan is so big you will not ever pay it off'. The idea that they will never pay off a loan is bad news for them. They want to pay it off," he said.
"If you start with the fees message, it is overwhelmingly negative. You need to say, 'Do what you want, so you can be all you can be'."
Students should be encouraged to focus on the fact that university is a "life-changing" opportunity, he added, and in particular an "intellectual experience". "I resent the private providers who say [a course] is just about getting 120 credits."
A spokesman for the student finance task force said Dr Harvey had misunderstood its purpose, which was "to ensure independent information is available...not to promote the benefit of going to university".
"We do advise that many graduates won't actually pay back their fees in full, and this is true," he added. "But equally we advise that some will end up paying much more."