Teaching unions in Wales have said that although they welcome changes being made to the English GCSE, they are unhappy with the timing of the move.
Earlier this month, it emerged that the Welsh government wants those in secondary teacher roles to switch to a new programme of study from mid-November, even though they have already started with the existing specification.
The move is a response to the summer's marking fiasco, which culminated in a row between Welsh education minister Leighton Andrews and the education secretary Michael Gove.
Mr Gove called his Welsh counterpart "irresponsible and mistaken" for ordering a re-grading of papers - after which Mr Andrews suggested Wales would break away from England and create its own examination system.
Apparently, this is now closer to fruition following schools director Chris Tweedale's letter to Welsh headteachers informing them of curriculum changes that will see less weighting given to coursework, Wales Online reports.
The exam board WJEC is drawing up the changes, which will be presented to those in teaching jobs in the near future.
However, Rebecca Williams, a policy officer with Welsh teachers' union Ucac (Undeb Cenedlaethol Athrawon Cymru), told the BBC that, although there is not an issue with the changes themselves, the Welsh authorities were making a mistake by implementing them now.
"The problem is with the timing because teachers began teaching this course and students started following the course in September," she said. "It's an extremely unusual step for the regulator to say we're changing the specification once it's already being taught."
However, a Welsh government spokesperson told the news provider that the amendments were essential.
"This subsequent change to the subject specification is vital to ensure that Welsh students can receive fair and just treatment when they sit their exams in 2014. We do not want Welsh students to be subject to grade boundary rules determined in England."
Posted by Tim Colman