A wave of 18 new strike days are planned across 150 UK universities in February and March, the University and College Union has announced.
It said a pay offer worth between 4-5% made during talks with employers this week was not enough.
But UCEA, which represents university employers, says the offer made is worth up to 7%.
UCU general secretary Dr Jo Grady said the "clock is now ticking" for a deal to be reached.
It comes after the government announced tuition fees in England will be frozen for another two years.
"Today our union came together to back an unprecedented programme of escalating strike action. The clock is now ticking for the sector to produce a deal or be hit with widespread disruption throughout spring," said Dr Grady.
University employers, the Universities and Colleges Employers Association (UCEA) say the offer on the table "recognises that cost-of-living pressures fall disproportionately on the lower paid staff".
UCEA chief executive Raj Jethwa said a proportion of the award on offer was being offered from February.
"This is six months early as a direct response to current cost of living concerns," he said.
UCEA said its offer would mean an increase of up to 7%, with a minimum of 5% for anyone earning up to £51,000.
"The fact that UCU is not calling indefinite strike action is welcome, but their revised strike plans could still have a damaging impact on students. UCU needs to provide its members with a realistic and fair assessment of what is achievable, " Mr Jethwa said.
The UCU said it would confirm the precise dates of strike action by the 70,000 academics and university support staff next week.
As part of the stepping up of its industrial action the union also said it would re-ballot members.
That would allow it to comply with the law on industrial disputes and open the way for it to call more strikes later in the year.
Pay and working conditions are the issues affecting every university caught up in the dispute.
The 3% pay increase this year is far below the rising cost of living, and the union said an offer of 4-5% tabled at a meeting yesterday was also not enough.
Many staff are also protesting at the use of short term insecure contracts at universities.
At the older universities – in existence before 1992 – there is also a separate dispute about proposed changes to the pension scheme.
For students the strikes mean more disruption to their courses, after many have already had their studies compromised by remote learning during the pandemic.
So far the National Union of Students has been broadly supportive of the industrial action. The BBC has contacted NUS for comment.
University staff previously held three days of strikes in November, in a dispute that has included calls for action to tackle "excessive workloads" resulting in hours of "unpaid work".
Academic staff and those in other professional roles including administrators, librarians and technicians have taken part in the strikes.
When are the next university strikes?
The strikes taking place in January
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