A third examiner has been suspended following allegations that she suggested a course was easy.
The chief examiner, from Edexcel exam board, was recorded by the Daily Telegraph saying the course content was so small she did not know how it had been passed by the regulator.
Edexcel says the examiner regrets making the comments.
Two examiners from another board were suspended after allegedly telling teachers which questions would come up.
The newspaper sent undercover reporters in to 13 seminars for teachers held in London by various exam boards.
The exam boards run them for teachers to give them "advice and support" in preparing their pupils for the exams.
Two inquiries have been launched in to the allegations - one in England and one in Wales.
The government has said fundamental reforms are needed in the exam system.
In the latest case, the examiner was recorded by reporters posing as teachers.
The paper says she said: "There's so little [in the course] we don't know how we got it through. And I'm deadly serious about that. When I looked at it I thought, 'how is this ever going to get through?'."
A spokesman for Edexcel said the examiner had been suspended - and regretted what she had said.
"Our examiners have a duty to uphold high academic standards at all times and like us, they should take this responsibility very seriously.
"In the video [the examiner] appears to imply that the standard of the specification is not as high as it should be.
"There is strong evidence that [the examiner] has not taken her responsibility to uphold standards seriously.
"We will investigate both this issue and the allegations regarding disclosure of future exam content, and during this, suspend her from her duties as an examiner. We will not pre-judge the outcome of any investigation."
The Education Secretary Michael Gove has said he will take any action necessary to restore confidence in GCSEs and A-levels, saying "nothing is off the table" and that exam boards could lose the right to set exams.
He expressed concern about a possible conflict of interest between the exam boards as businesses and exam standards in a recent letter to England's exams regulator, Ofqual.
He said there was a "significant risk" of awarding bodies producing "less challenging" content and exams to get schools to choose their exams over those of other exam boards.
Schools pay exam boards to sit their exams.
Ofqual is to look at the issue - and that of companies associated with exam boards selling text books and study aides.
It is understood the heads of the exam boards covering England, Wales and Northern Ireland will be called in front of MPs on the Commons Education Select Committee next week.
The committee was already looking at the exam system - but an emergency hearing is being arranged following the recent controversy.