Education secretary Michael Gove's announcement of changes to the A-Level exam system has given "added pressure" to education publishers as they wait for details to be confirmed.
Gove said last week that he will return A-Levels to two years of study with an end-of-course exam. In September he said GCSEs would be scrapped in favour of "tougher" O-Level style exams.
Kate Harris, m.d. of Oxford Education, said: "The UK secondary market is constantly evolving, with a number of curriculum and qualification reforms in recent years. This has added pressure to a fast-moving sector, with already tight publishing schedules."
A spokeswoman for Nelson Thornes said: "At the moment it is difficult for anyone in the industry to predict the full extent of the government's planned changes for education. As publishers we shall be waiting for these decisions to be confirmed before we develop suites of resources, and then we would look to be in a position to help support teachers in their delivery of the new curriculum."
Pearson meanwhile welcomed the delay in the changes to the A-Level programme from 2014 to 2015 as "sensible".
Harris added: "It's crucial that the market remains open and encourages variety and choice, so that publishers can continue to create a range of high-quality resources for all teaching and learning needs."