Some university vice-chancellors are being paid as much as 13 times the median pay of their staff, the university regulator has revealed.
The Office for Students data also shows 62% of universities in England raised the number of staff paid over £100,000, between 2016-17 and 2017-18.
The government says the OfS can require universities to justify high pay.
But the University and College Union said its "lightweight" report exposed the regulator as a "paper tiger".
The universities with the greatest increases in vice-chancellor pay were:
- De Montfort University - from £286,000 to £350,000
- Bishop Grosseteste University - from £158,000 to £188,000
- The University of West London - from £266,000 to £306,000
- The University of Essex - from £257,000 to £289,000
- Anglia Ruskin University Higher Education Corporation - from £257,000 to £289,000
OfS chief executive Nicola Dandridge said: "It is good to see signs of pay restraint at some universities, with some vice-chancellors refusing a salary increase.
"A number of governing bodies have reduced the basic pay of their vice-chancellor, though we acknowledge that it can be difficult to revisit contractual obligations while a vice-chancellor is in post.
"We expect to see further progress next year."
But the University and College Union said the regulator had failed to keep its promise of requiring universities to justify annual salaries above £150,000.
The report showed only four institutions out of 133 paid their vice-chancellor under £150,000 (in total remuneration) but contained no details about the justification for those awards, the union said.
And it failed to look at the "excessive and arbitrary rises still enjoyed by some vice-chancellors" or tackle the expenses and other benefits in kind that have "plagued universities in recent years".
In its conclusion, the report says: "Publishing information about remuneration and compensation for loss of office ensures this information is in the public domain.
"Where this is a matter of public interest, transparency will help providers' remuneration committees and governing bodies to benchmark more effectively."
Education Secretary Damian Hinds said: "We set up the Office for Students to look out for students' interests and it is absolutely right that the OfS demands greater transparency from universities by requiring them to justify the pay and benefits of their vice-chancellors.
"We have given the OfS powers to take action if universities do not do this and we expect them to be used where necessary."
He added: "Of course salaries need to be competitive - but high pay must be justified by high performance on objectives such as widening participation for disadvantaged groups, low dropout rates, growing export earnings and pioneering innovative research."