School-leavers could find it harder to get into UK universities because of competition from thousands of candidates from the new European Union member states, according to an independent think-tank.
Some 30,000 extra students are expected to seek places at UK universities when the ten accession countries - including Cyprus, Poland, Malta, Hungary and the Czech Republic - join the EU on May 1.
Up to 250,000 extra university places are already needed by 2010 to meet increased demand from home students because of demographic growth and improved exam results among school-leavers.
Libby Aston, senior researcher at the Higher Education Policy Institute, said: "Whether we will see a shortage of higher education places in the UK for the first time in decades will depend on the availability of government funding for additional places.
"If supply does not increase sufficiently to meet demand, it is not just EU students who will lose out - the number of higher education places available will not be sufficient to meet demand from home applicants either and this could reduce UK participation rates."
But Alan Johnson, the higher education minister, said: "We have factored EU accession-state students into future projections for both planning and student-support purposes and will continue to do so in the next spending review.
"We do not anticipate large rises in EU student numbers because we do not give maintenance support to students from the EU and so coming to study in the UK will not be a cheap option."
The Hepi study found that growth in EU student numbers will increase competition for places at selective universities that pick the most academically able students, irrespective of their background or country of origin.
The projected increase in the pool of qualified entrants will benefit those institutions that have to actively recruit rather than those that select students from only the best applicants.
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