University bosses' "pay and perks" should be published so they are open to public scrutiny, it has been suggested.
The University and College Union called for the information to be released in a public register as it warned that "largesse" by university leaders has become an "embarrassment".
The call comes amid a growing debate about inflation-busting pay hikes for vice-chancellors at a time when university tuition fees stand at up to £9,250 a year.
On Thursday, Lord Adonis, who served as education minister under the last Labour government, raised fresh concerns about the high salaries awarded to some university leaders.
Universities minister Jo Johnson has issued a call for universities to show restraint on pay, warning that there should not be an ''endless upward ratchet'' of salaries.
UCU general secretary Sally Hunt said a public register of pay and benefits was needed to restore public confidence, particularly as universities receive taxpayers' money.
"The largesse of those at the top of our universities has long been a source of embarrassment for the sector and UCU has raised the issue many times with ministers," she said.
"With the amount of debt students are accruing to fund their education under the spotlight, the time has come to expose the murky world of senior pay in universities.
"The huge disparities in the levels of pay and pay rises expose the arbitrary nature of vice-chancellors' pay.
"It is simply wrong that some of them sit on the committee that decides their pay and that universities can hide behind its shadowy remuneration committee's decisions without releasing minutes from the meeting.
"Years of politicians calling for restraint at the top of universities has fallen on deaf ears and they have to recognise the need for a proper public register of pay and perks which can be scrutinised by the public, including the students who are funding these pay hikes."
A UCU analysis published earlier this year concluded that university heads received an average pay package, including benefits of £277,834 in 2015/16.
Speaking in the House of Lords, Lord Adonis highlighted the pay packet awarded to Bath University vice-chancellor Glynis Breakwell.
"Last year, the vice-chancellor earned £406,000," he said.
"This year, despite the 1.1% cap on pay for non-managerial staff across the higher education sector, the vice-chancellor's pay rose by 11% to £451,000," Lord Adonis said.
Prof Breakwell's accommodation is a large house in the centre of Bath, he noted, adding: "Put all that together, and Glynis Breakwell is paid almost exactly half a million pounds, more than three times the prime minister's salary."
"The highly paid should set an example to the rest of the community, particularly at a time of pay restraint. The only example the vice-chancellor of the University of Bath is setting to her staff is one of greed," Lord Adonis told the Lords.
A Bath University spokesman said Prof Breakwell's salary and conditions are determined independently by a remuneration committee and comparable with that of other long-standing vice-chancellors at successful institutions.
"The increase reported in the 2015-16 accounts reflects her excellent track record and the confidence placed in her leadership of the senior team and the wider University community."
Mr Johnson said last month: ''There are legitimate concerns about the rate at which vice-chancellor pay has been growing.
''I think it is hard for students, at a time when they have concerns over value for money and want to see real evidence of value for money from their tuition fees.
''They do have concerns about the rate of growth in vice-chancellor pay.
He added: ''I don't think we need to accept an endless upwards ratchet, and I would urge them to show the kind of restraint that I've been calling for for some time now."
Lord Adonis has previously suggested that university tuition fees are leaving students with ''Frankenstein's monster'' debts and should be scrapped entirely.
He argued that the current cost of tuition for many is the result of ''opportunism and greed'' - largely on the behalf of university bosses who enjoy high salaries while many graduates on modest incomes are left with unpayable debts.
In a blog post for the Times Educational Supplement (TES), Tim Bradshaw, acting director of the Russell Group - a group of 24 leading universities - said it was right that students make some financial contribution towards their studies.
But he added the system could be examined to see how it can be made fairer.
The interest rate on student loans will be up to 6.1% from this September, which is "out of touch with commercial lending rates, and very high compared with the rates at which the Government can borrow," Dr Bradshaw said, adding that this could be reassessed.
Under the current system, graduates begin paying back loans when they are earning at least £21,000. This could be reconsidered, Dr Bradshaw said.
He also suggested changes to how repayments are made, such as being able to make payments through salary sacrifice schemes.