Most universities radically reduce monitoring by gender, race and disability once someone is appointed, according to Natfhe, the university and college lecturers' union.
The union yesterday launched a drive to open up promotion prospects for women and other disadvantaged groups.
Liz Allen, Natfhe's chief higher education negotiator, told an Arbitration and Conciliation Advisory Service conference that most universities monitored appointments, but very few monitored the promotion process.
Statistics show that between 1991 and 1992, the number of female academics in the new universities and colleges of higher education rose by 11 per cent, compared with a 2 per cent rise in the number of male academics.
But women were still primarily employed in the lower grades and in newer, less secure posts, such as in research. Women accounted for per cent of academic staff, but 46 per cent were on the lowest lecturer grade. Women only had 18 per cent of the principal lectureships and 15 per cent of head of department posts.
Dr Allen said: "There is an inbuilt tension between deregulation and decentralisation of employment practice and equal opportunities legislation. Increasing middle managers' freedom to decide what to pay new staff, when to hire and fire part-timers, and how to reward added responsibilities, potentially exposes institutions to discrimination and equal pay claims."