The Labour-controlled Welsh Assembly may abandon its opposition to top-up fees even if it gets devolved powers over student funding as expected.
The admission came after the Liberal Democrats circulated a letter from Welsh secretary Peter Hain to Welsh Labour MPs in which he set out the assembly's thinking on student finance.
In the letter, Mr Hain says: "Welsh Labour stood on a platform this year of ruling out top-up fees in Wales for the period of this assembly term.
"However, as in the UK, that does not mean that the assembly should not explore all options for the future funding of universities in Wales during this term, for implementation in the next - these options will include fees."
Peter Black, the Welsh Liberal Democrat education spokesman, said the letter proved the assembly was "preparing to abandon its opposition to top-up fees" after the next assembly elections in 2007.
He said: "The implications of this letter are clear - the education minister [Jane Davidson] has consistently said that she is opposed to top-up fees for higher education students, and yet this letter from the secretary of state for Wales reveals that she and her colleagues in Welsh Labour are considering their introduction in the next assembly term."
He said such a move would deter would-be students.
An assembly spokeswoman said that although a promise not to introduce variable fees before 2007 was one of the assembly's top ten commitments, "it has been made clear that this does not rule them out in the longer term".
She added: "The line from Peter Hain's letter that the assembly will explore all options for the future funding of universities in Wales, including fees, therefore does not represent any break with what the assembly government has already said.
"As well as an obligation to students who study in Wales, we have an obligation to ensure that our institutions are well funded and can compete on the world stage."
An announcement on whether Westminster will devolve powers over student finance to the assembly is expected in early December after the higher education bill introducing top-up fees in England is published.
The assembly will then begin an independent study into all issues relating to top-up fees, chaired by Teresa Rees of Cardiff University, before deciding how to proceed after 2007.
- Jim Wallace, Scotland's deputy first minister and minister for lifelong learning, attacked the government's proposals for top-up fees saying they make entry to higher education dependent on chequebooks rather than on merit, writes Olga Wojtas. Mr Wallace, speaking at the National Union of Students Scotland's annual reception in Edinburgh, said the Scottish Parliament's decision to scrap tuition fees had been "an important step in widening access".