Education Secretary Michael Gove has expressed his anger at errors in this year's GCSE and A-level exams as details of three more blunders were revealed.
Students issued fresh calls for Mr Gove to launch an investigation into the mistakes, amid concerns about the impact on grades and university places.
It came as two of England's biggest exam boards were forced to apologise again after errors were discovered in two GCSE papers and an A-level exam.
One board, OCR, said it "deeply regretted" the mistakes and said jobs may be lost as a result.
A Department for Education spokesman (DfE) said the errors are "completely unacceptable".
"The Secretary of State is angry about these and other errors. He has said repeatedly that the exam system is discredited and action must be taken. The Department has been in close contact with Ofqual and the Secretary of State is speaking to them today to get a briefing on what action they are taking."
Shane Chowen, National Union of Students (NUS) vice president (Further Education) said: "Despite calls to ensure they avoided further mistakes, exam boards are creating confusion and failing students. The responsible exam boards must be compelled to pay for students who have been disadvantaged by these errors to resit.
"Two weeks ago I called on Michael Gove to instigate an immediate investigation but we have so far been met with stony silence."
Earlier this month, Ofqual chief executive Glenys Stacey wrote to exam boards warning them there must be no more mistakes and that urgent extra checks should be put in place.
Ofqual later confirmed it is looking into nine mistakes, as well as a small number of other issues and complaints about exams.