Secondary students say it's unrealistic for the ASTI to demand the Leaving Cert go ahead as normal this year.
The union withdrew from talks last night, saying a proposal to blend the traditional exam with calculated grades is "unviable".
In a statement issued yesterday, the secondary teachers' union says the Department of Education is placing too much emphasis on caculated grades.
The Department says it's "taken aback and disappointed" and will continue discussions with other groups.
A fresh round of discussions aimed at finding a solution will begin today between the union and the Department of Education.
Reuben Murray, president of the Irish Second-Level Students' Union, says the row is only piling on the pressure: