Welsh university heads have said they can see "no viable alternative" to introducing top-up fees.
The first collective statement from Welsh vice-chancellors on the question of whether they support variable fees was issued on Tuesday by their representative body, Higher Education Wales.
It followed a Hew committee meeting at which vice-chancellors voiced growing unease over the Welsh Assembly's uncertain plans for funding higher education.
The assembly has pledged not to introduce top-ups for the lifetime of its term, until April 2007, and has promised that Welsh universities will not be financially disadvantaged compared with English universities as a result.
But it has refused to say how much compensation Welsh universities will get or where the cash will come from. It has also launched a review of Welsh higher education funding to help it decide what to do beyond 2007.
But the review cannot start until the higher education bill gets royal assent and student funding powers are devolved from Westminster to the assembly. The vice-chancellors have complained that this uncertainty makes it difficult to plan finances and to inform students about fees.
Hew's statement says Welsh universities must not be financially disadvantaged compared with English institutions if they are to deliver on assembly higher education targets.
It adds: "Because Hew considers that the possibility of finding sufficient funds to do this from general taxation is remote, it can see no viable alternative to the introduction of a scheme for graduate contributions comparable to that which is now almost certain to be introduced in England.
"Should an alternative exist, it must be identified without delay and introduced simultaneously with arrangements in England."
Jane Davidson, assembly education minister, said variable fees had not been ruled in or out beyond 2007.
The Hew statement was immediately condemned by student union leaders. James Knight, deputy president of NUS Wales, said its comments were "incredibly disappointing".