Union leaders have criticised pay rises given to the vice-chancellor of the University of Sussex, saying they outstrip increases given to other members of university staff.

The Association of University Teachers (AUT) says Professor Alasdair Smith's pay has risen at more than twice the rate of tutors' pay in the past eight years.

The AUT has released figures suggesting the vice-chancellor's salary increased by 58.1 per cent between 1994 and 2002.

In the same time, lecturers at the university have seen their monthly wage increase by a total of 25 per cent.

The AUT figures come as a postal ballot for strike action over pay modernisation draws to a close.

It says the results of the study - which reveal some vice-chancellors have enjoyed 70 per cent pay rises since 1992 - will fuel anger among support staff and lecturers already upset at the proposed changes to their pay structure.

Oxford-educated Prof Smith became Sussex's sixth vice-chancellor in 1998. His wife works as a tutor at the university.

Prof Smith decided to break with tradition and not live in Grade I listed Swanborough Manor, just outside Lewes, when he took on the job.

The couple and their two children share a semi-detached house in Lewes.

Prof Smith earned £128,000 in 2002 but his salary is dwarfed by the highest-paid vice-chancellor in England.

Laura Tyson, from the London Business School, earns £316,000.

Prof Smith has called for the introduction of top-up tuition fees and criticised Brighton and Hove City Council for opposing them.

The AUT's Sussex president Jim Guild said: "Year after year, tutors have been told by Prof Smith there isn't enough money to pay much above the rate of inflation.

"And yet we now find he has been awarded pay rises amounting to 58.1 per cent.

"This is hugely demoralising and upsetting."

AUT researchers claim the pay reforms would lead to lecturers losing £6,000 over eight years, researchers losing £17,000 in nine years and senior support staff losing £47,000 in 21 years.

The National Union of Students (NUS) has backed the AUT's decision to hold a strike ballot.

NUS president Mandy Telford said: "We urge employers to return to the negotiating table to resolve the AUT's issues now, in order to protect the high quality of education for current and future students."

If AUT members support the strike, universities will suffer a week of disruption from February 23.

Prof Smith said lecturers and university staff had not complained to him about the gulf between his pay rise and theirs.

He said: "It is for the university to comment on my salary.

I have always made it clear academics other than vice-chancellors are underpaid."

Talking about the proposed pay reforms, he said: "I approve of a new national pay framework for higher education and the new framework has been welcomed by the Transport and General Workers' Union, Amicus and Unison.

"The AUT are seeking to maintain status differentials between different members of staff that are not justified in the 21st Century."

Barbara Bush, Sussex University's director of human resources, said: "In 1994/5, Prof Smith was not the vice-chancellor of the university. He took up his post in July 1998.

"Last year he declined a pay award altogether."

The vice-chancellor's salary is set by the university's remuneration committee.