Fresh talks to break the deadlock in the classroom assistants strike have been continuing throughout Saturday.
Nipsa's John Corey said the employers must be prepared to reach a deal
The Labour Relations Agency said it had invited management and trade unions to meet with its officials in Belfast, and that both sides have accepted.
About 3,000 members of Nipsa are staging an indefinite strike over pay and job re-grading.
Speaking on his way into the meeting, Nipsa's John Corey said the employers must be prepared to reach a deal.
"It was shameful that they (the classroom assistants) have been forced to take strike action for nine days now, in order to get to this point where the employers are prepared to come into the room to start addressing the issue," he said.
"I have said I hope the employers come here today determined - along with us - to find a resolution to this dispute in the interest of all parties."
The idea of going to the LRA was ruled out earlier this week by the Department of Education and the education and library boards, who said it was "too soon to intervene".
Now they say they are responding to the favourable reaction of unions to the idea and will allow talks to take place.
The BBC's Education Correspondent Maggie Taggart said that one problem seems to be that the employers were insisting that they want to clarify their existing offer rather than make a better one.
The talks at the LRA began at 1000 BST on Saturday.