Universities involved in delivering degree programmes overseas may be at risk of saturating certain markets, government research suggests.
The study, conducted for the Department for Innovation, Universities and Skills, paints a picture of ad hoc expansion of "transnational education", with strategic planning coming after successful enterprises rather than before.
Although broadly positive, it describes pockets of concentrated provision in some subjects, with the sector's market-led approach also leading to a focus on particular countries and types of partner.
The report says: "There may be implications here for sustainability, competition and duplication between UK higher education institutions."
Another area of concern is the type of partner that UK universities work with to deliver programmes overseas, where sustainability is again an issue. The analysis warns that the focus on private colleges as partners may become "problematic" if those institutions gain their own degree-awarding powers.
The research is based on a survey of the UK's higher education sector, with 82 per cent of institutions taking part.
Of the 135 that responded, 65 per cent offer transnational education, with a combined total of 1,536 programmes and 6,000 students between them.
The largest providers are post-92 universities, which account for 63 per cent of provision, followed by pre-92s, which offer 31 per cent.
The study found that nine out of ten large institutions were involved in this area, 70 per cent of medium-size institutions and 35 per cent of small institutions.
Many subjects are offered, but some are far more prevalent than others, with business and administrative studies accounting for more than a third of all programmes.
Other common subjects include maths and computer sciences, creative art and design, engineering and medicine, with this top tier accounting for 85 per cent of all provision.
The analysis found transnational education involving UK universities to be widespread, delivered in almost 80 countries worldwide. Regionally, Asia has 44 per cent of courses, the largest proportion, followed by Europe with 28 per cent.
In Europe, there are more postgraduate programmes than undergraduate - 243 compared with 172 - while in Africa, Asia and the Middle East the reverse is the case.
This indicates that in some regions the key function of transnational education is to top up shortfalls in undergraduate provision, whereas in others it is to develop high-level academic knowledge and skills, the study says.
In a speech last week, Bill Rammell, the Higher Education Minister, described internationalisation as a "great success story" for UK universities. He said: "While famous names and ancient institutions may find it easier to persuade students from other countries to come here to learn, what our newer universities can offer is also in demand, and they are finding new ways to deliver it."