Ministers face tough choices over how they fund universities in Wales in the future, they have been warned.
Professor Sir Deian Hopkin, former chairman of the Student Loans Company, said Wales could follow England and look to increase tuition fees.
Alternatively the assembly government could fund universities directly.
But he said that could lead to an influx of students from England looking for "cheaper" degrees and it could be difficult to strike a balance.
The UK government has announced plans to raise fees for students in England to a maximum of £9,000 per year, with universities facing obligations to act to recruit more students from disadvantaged backgrounds if they want to charge more than £6,000.
At present in Wales fees are capped at £3,290. Until 2010-11, all Welsh students studying in Wales were given a grant of £1,890 towards their fees.
Welsh education minister Leighton Andrews has said the assembly government estimates it will cost between £70m and £110m to fund the increase for students from Wales studying in England.
Professor Hopkin said the assembly government was "between a rock and a hard place" in deciding how to fund universities in Wales.
"The reality is its not just about fees, the fees are going to have to rise [in England] because the government has cut the amount of direct money going into universities," he told the BBC's Good Morning Wales radio programme.
"That means universities have to increase their fees simply to fill the gap.
"Does Wales cut direct funding in the same way or does it in fact try to balance it and have a slightly different mix?
"That has consequences because it might make Wales very attractive to students fleeing across the border."
Katie Dalton, president of the National Union of Students in Wales, said the changes planned in Westminster would "obviously have an impact" on students in Wales.
"I would say that we've got a good student support settlement in Wales - we've got £5,000 in grants for the very poorest students.
"The decisions that the Westminster government are making could have considerable impact in Wales."
Liberal Democrats education spokeswoman in the assembly Jenny Randerson told Radio Wales there were many members of her party who were "extremely unhappy" with the UK coalition government's plans.
But she said universities in Wales already suffered from a "massive funding gap" compared to their counterparts in England.
"We accept that because of the Browne Review that inevitably means there will be an increase here in Wales," she added.
"I'm not keen on seeing the very large fees that have been talked about in some large universities in England."