Talks in the university pension dispute resumed at noon on Tuesday after overnight skirmishes on Twitter.
Talks had been suspended until Wednesday after Monday’s meeting at the offices of the conciliation service Acas ended without agreement.
Staff at 64 universities say pension cuts will cost them an average £10,000 a year, but the employers say the scheme has a deficit of more than £6bn.
About 126,000 students have now signed petitions calling for fee refunds.
The University and College Union blamed the employers’ organisation Universities UK for the fact that talks would not resume until Wednesday.
But Universities UK responded on Twitter that they were prepared to meet “any time, any place for talks”.
Interchanges between UUK and academics on the social media platform overnight resulted in a new round of talks, starting at midday on Tuesday.
The employers’ organisation Universities UK wants the Universities Superannuation Scheme to change from a defined benefit scheme, giving members a guaranteed income in retirement, to a defined contribution scheme, where pensions are subject to changes in the stock market.
On Monday the University and College Union tabled alternative proposals to reform the scheme which it said would involve universities accepting some increased risk and small increased contributions of employers and scheme members.
UUK originally said that it needed Tuesday to cost the union’s proposal, saying that it feared it would require “very substantial increases in contributions” which would not be affordable – but some vice chancellors have voiced support for UCU’s plan.
On Tuesday morning a UCU spokeswoman said: “We are not interested in the game playing, and welcome the fact that they have now agreed to more talks today.”
With a further eight days of strikes due to take place before the end of next week, UUK wants industrial action called off while talks continue.
Last week universities minister Sam Gyimah urged institutions to offer compensation to students for teaching hours lost during the dispute.
The dozens of petitions calling for refunds are largely supportive of the strikers.
Kings College London has said it will ring-fence any salary savings as a result of the strike action as a fund which it would use to offset the impact of the strike on students.
A spokeswoman said it was too early to say whether this would mean refunds for all students or a contribution to the student hardship fund.