A £15m project to expand the University of Glamorgan's Cardiff campus has been put on hold.
The university's Atrium campus was due to be extended to house up 1,200 more students and scheduled to open by September 2014.
But sources say the plans have been shelved, partly due to falling student numbers.
In a statement, the university said its "commitment to expansion in Cardiff remains solid".
The University of Glamorgan is in the process of merging with the University of Wales, Newport, by autumn 2013.
When the expansion was announced in March, the university said it was aiming to add up to 1,200 students to its School of Creative and Cultural Industries.
BBC Wales has learnt that the total number studying at the University of Glamorgan - including its Treforest campus near Pontypridd - was far fewer than expected this year.
One source told BBC Wales it was 800 students fewer.
A University of Glamorgan spokesperson said: "We are working with designers on plans for the development of our Cardiff site, and the decision on when options to accommodate our growth come into service will be undertaken in 2013.
"Phasing in Atrium 2 over this period means that we can assess what is happening in the currently unpredictable higher education market and make timely decisions on when this development comes online and dovetail the development with our plans for the new university."
University student union president Ashley Price said plans have been reassessed since student numbers were not as high as expected.
"I think this is a reflection of a volatile market," he said.
"The tuition fees increase... is going to have a knock on-effect."
Originally the Polytechnic of Wales at Treforest, Pontypridd, the University of Glamorgan opened the Atrium campus in Cardiff in 2007.
It is also responsible for the Royal College of Music and Drama in Cardiff and a new tertiary college in Merthyr Tydfil.