Students could face subject "cold spots" if universities are not allowed to work together more to deliver courses, according to a new report.
The review by Universities UK, which represents 141 institutions, found universities were reluctant to collaborate because of concerns around breaking business laws designed to promote healthy competition between them.
The Competition and Markets Authority (CMA) said it wanted to support collaboration where possible in a "very challenging" financial situation for the sector.
A government review of how higher education will be funded in the long term is under way in England, and is expected to be published later this year.