Scores of academics earn more than First Minister

Other principals earning large salaries include Louise Richardson at St Andrews, on about £240,000; Professor Anton Muscatelli at Glasgow on £257,000 and Professor Sir Timothy O'Shea, of Edinburgh, on £227,000.

Glasgow Caledonian University principal Pamela Gillies earns more than £180,000 a year, although she did agree to take a 2% cut in 2010.

More than half of the staff members listed are at Edinburgh University – although this can be partly explained by the high proportion of consultants who teach at the medical school and whose salaries are paid jointly by the institution and the NHS.

The figures also show a growing disparity between the best-paid university employees and the lowest-paid.

NUS Scotland called for restraint, saying it was "unjustifiable" for university principals and other senior staff to be paid such high sums.

However, Universities Scotland, which represents university principals, argued the salaries were proportionate to the significant role played by senior staff in leading multimillion-pound institutions.

The figures emerged as a new code of conduct for university governance in Scotland is about to be published.

The code will look at a range of issues such as the democratic make-up of the ruling bodies, their gender balance and whether chairmen should be elected. The original intention of the code was also to look at the salaries of principals.

Robin Parker, president of NUS Scotland, said: "Across our institutions, the gap between the lowest and highest-paid is too large, with some receiving almost 20 times that of the lowest-paid university employee.

"Universities need academic autonomy, but they should not have the freedom to pay such large salaries and to allow large gaps between those at the top end and the lowest-paid. Hundreds of millions of pounds of public money are quite rightly going into universities over the next few years. We must make sure this money is used on the front line, not on increasing already substantial senior salaries."

Mr Parker said the new governance code provided the opportunity to start addressing the pay imbalance.

A spokesman for UCU Scotland, which represents lecturers, said it was "galling" to see the salaries of principals and vice-principals.

"The lack of self-awareness from university leaders when it comes to their own rewards continues to be an embarrassment for the sector, especially when we consider the recent promises that their pay and perks would be reined in," he said. "This is why we are calling for the review of governance to redress the balance back towards collective responsibility and away from the idea that education is all about profit and loss."

However, Universities Scotland said it was unreasonable to compare universities to public-sector organisations such as local authorities.

Its spokesman said: "Universities do receive a significant level of public funding, but this is a minority of their total income with over £1.6 billion, or 56%, of the total coming from private and competitively won sources. As a result these salaries are not wholly paid for by the public purse, unlike those in public-sector organisations.

"The highest-paid university staff tend to be senior clinical academics who are employed jointly by the university and the NHS. This is usually what accounts for salaries over £250,000 in the very limited number of cases this occurs."

He added that salary levels are determined by NHS terms and conditions and not all of the salary is paid by the university.

The spokesman also pointed to a recent analysis, which found Scotland's universities have moved to show restraint in principals' pay, as the average increase was 1%. He added: "At many universities, principals' pay has remained static over the last year or has actually decreased."