Tuition fees of Pounds 1,000 a year could quickly rise, Sir Ron Dearing has warned students.
There can be no guarantee that fees will stay pegged at 25 per cent of course costs, he told a meeting of student union chiefs this week.
Sir Ron said his committee had tried its best to safeguard the rate of the new levy. But he acknowledged that under a similar scheme in Australia, the amount asked of students had risen quickly.
"We understand your concerns that once we open the box, the Treasury will widen the lid. I cannot guarantee that won't happen," he told delegates at the meeting at King's College in London.
He said most of the evidence received by the committee had recommended scrapping maintenance grants rather than introducing fees. But the main problem with this was "it didn't produce the readies". It also appeared to threaten access for the poorest students.
Sir Ron said the favoured government option was "not as favourable to those youngsters as our proposals".
He was also concerned that government plans to withdraw the maintenance grant, against the recommendation of his committee, could threaten participation.
"I would say that the government system will leave those from poorer backgrounds with bigger debts," he said. Giving priority places to institutions with well worked-out participation policies was essential, otherwise "there could be damage".
Sir Ron urged students to press the Government for more money for higher education. The committee had favoured tuition fees rather than changes to maintenance arrangements because it wanted to ensure the extra money went into the sector.
"Don't assume it's an easy job for the secretary of state to secure the debates in government for more money for higher education," he said. "We propose big increases in funding which are needed to avoid damage to higher education now and in the next two years. Someone has to fight for the change in the cuts which were proposed, someone has to fight for more money for access, someone has to fight for more money for research and for information technology."
Students vowed to devote their energy to fighting tuition fees.
Campus ballots will be held over the summer with a view to organising demonstrations by the beginning of next term.
Doug Trainer, president of the National Union of Students, said: "We have to take the message out of here to employers to say they have to pay more, and to parents and sixth formers to explain what is happening. Let's hit the campaign trail running."
Tara Emery, University of Kent student union president, said: "We are totally opposed to fees and will fight them all the way."
Lynn Butler, education officer at the University of Central England in Birmingham, said all the city's institutions would join together in the campaign.
Diana Warwick, chief executive of the Committee of Vice Chancellors and Principals, warned even the Government's proposal might not be able to "deliver the goods".