Last-minute talks will be held on Monday in a bid to resolve a teachers' pay dispute ahead of planned strikes this week.
Members of the National Education Union (NEU) in England and Wales are due to walk out on Wednesday, with more industrial action planned in the following weeks.
Union leaders will meet Education Secretary Gillian Keegan in a final attempt to break the deadlock.
Kevin Courtney, joint general secretary of the NEU, said: "This is the last chance to avoid the strike on Wednesday.
"However, on Friday the Department for Education failed to meet the deadline to its evidence to the teachers' pay review body.
"We can only assume this is because they know that their recommended increase for teachers' pay will not be acceptable to our members and will contradict the evidence they must have put in about teacher recruitment and retention difficulties.
