Education Secretary Michael Gove today 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."
Students taking a GCSE maths exam this morning were given a paper containing questions from an old exam.
Due to a printing error, the paper, set by the AQA exam board, included questions originally answered by pupils in March.
AQA said up to 2,500 students out of the more than 31,000 who sat the exam were given the incorrect paper.
It added it was "very sorry that this has caused some students distress this morning".
A spokesman for the OCR exam board apologised for two mistakes uncovered today, saying it "deeply regrets" the errors - one in a GCSE Latin paper, and the other in an A-level physics exam.
The Latin GCSE paper, taken by up to 8,000 students, contained incorrect names of writers and characters.
The errors affected three questions, two of which were worth two marks each, while the third was worth 10 marks.
The physics A-level paper, sat by almost 8,000 students, contained a measurement given in both centimetres and metres, when it should have been in metres only. One question was affected, worth two to four marks.
An OCR spokesman said: "We deeply regret these errors.
"We are extremely angry, because this is not fair on students, parents and teachers."
He added: "It is not acceptable, and if we find that someone has not done their job, they will lose their job."
The board said it was assuring students they will not be put at a disadvantage due to the mistakes, and examiners will take them into account when deciding how to mark the papers.
The errors are the latest in a string of blunders.
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.
An Ofqual spokesman said: "Each awarding organisation is responsible for the quality of its exam papers and knows that such errors are unacceptable. We received assurances from each of them last week that additional checks had been carried out and will now be seeking explanations as to why these errors still occurred, and we will take regulatory action as necessary.
"These latest incidents are unwelcome and unacceptable. The awarding organisations are investigating and we expect more information shortly.
"We will be monitoring their responses and will require them to make sure that as far as possible no candidates are unfairly advantaged or disadvantaged."
Tens of thousands of teenagers have now been hit by errors, with many previously raising concerns that their grades could be affected, which could in turn impact on university offers.
Some are worried they wasted time answering questions that contained mistakes.
The other mistakes to come to light so far, are:
:: Students sitting an AQA AS-level geography exam on May 24 were given the wrong information in a question worth four marks which asked them to label the fastest part of a river.
:: Sixth-formers taking an AS-level AQA computing paper on Tuesday were faced with an arrow in a diagram that was shorter than it should have been.
:: A multiple choice question featuring four wrong answers in an Edexcel AS-level biology paper sat by 17,000 students;
:: Students sitting an AQA AS-level business paper were faced with a question, worth a maximum of three marks, that did not include the information needed to come up with an answer;
:: A maths AS-level paper, set by the OCR exam board, and taken by 6,790 pupils, also contained an unanswerable question. The question, which was worth eight marks - 11% of the paper, was impossible to solve as it was incomplete.
:: There was also a mistake in a GCSE business studies paper set by CCEA, the exam board in Northern Ireland.
Ofqual later confirmed it is looking into nine mistakes, as well as a small number of other issues and complaints about exams.