Universities fear that the Government is considering a second substantial hike in visa charges with potentially disastrous consequences for overseas student numbers.
The Government came under fire from universities and Ukcosa, the Council for International Education, two years ago when it pushed up visa charges by 150 per cent and doubled visa extension charges.
Opponents pointed to the recent decline in the number of international students as a warning against a further rise.
Now Ukcosa is concerned that questions raised by the Home Office in a consultation on new immigration charges, point to further plans for a significant rise in visa fees.
The consultation, which ended just before Christmas, was conducted as part of the preparation for the introduction of a new points-based immigration system, which is due to start at the end of the year.
Ukcosa said this week that it was concerned that some of the questions in the consultation, such as whether visa charges should be set to reflect their market value, signalled an intention by the Home Office to raise visa fees further.
Dominic Scott, Ukcosa's chief executive, said the questions were particularly ominous because the consultation paper failed to give any guidance on how visa charges could change under the new system.
He said: "The Home Office is planning to introduce a new computer system and employ 150 new enforcement officers to support its new scheme. We want to know the cost implications of all of that.
"We are concerned that they are loading so many additional factors into the system, with all this focus on policing our borders, that costs and visa fees will rise substantially."
A Universities UK spokesperson said: "We look forward to the response to the recent Home Office consultation on the current visa regime. We would obviously hope that it takes into consideration the benefits that overseas students and academics bring to the UK.
"It is crucial for our universities and the economy that the UK offers a truly welcoming and supportive environment for overseas students and academics to live and work in.
"It is also important that any new system does not place too many additional financial or bureaucratic burdens on our members."
This week's warning coincides with an outcry from Ukcosa and the UUK over new working restrictions coming into force this month that will, in effect, ban Bulgarian and Romanian students from joining sandwich courses in Britain.
Under the new rules, Bulgarian and Romanian students will be denied the right enjoyed by all other international students to work full time during vacations.
Ukcosa and UUK argued that the restrictions were in conflict with European Union laws that state that people from accession countries cannot be placed in a less advantageous position than they were in before their country became part of the EU.
Mr Scott said there were concerns that, with 2,400 Bulgarian and Romanian students currently in the UK, the regulations would not only cause serious problems for the students affected but would also harm international recruitment efforts.