The education minister has accused a teachers' union of being "incredibly disingenuous" over claims that it did not instruct its members not to return to schools.
Norma Foley said unions had made it clear they were not happy to accept pubic health advice.
She made the comments after John Boyle, general secretary of the Irish National Teachers' Organisation (Into), insisted the union did not instruct its members not to go to work on Thursday.
On Tuesday night, the Government confirmed its decision not to reopen schools for primary pupils with special needs on Thursday after unions rejected the plans.
The Department of Education said it will "regrettably" not be possible, blaming a lack of co-operation by key unions in the primary sector.
Into and Forsa, which represents 15,000 non-teaching education staff such as special needs assistants, said efforts to reassure staff that it was safe for schools to open limited services to pupils with special education needs (SEN) had failed.
Staff and unions had raised concerns about high levels of infection in the community.
Ms Foley told RTÉ's Morning Ireland that the public health advice given to unions and staff was "categorical and unequivocal".
Asked about Mr Boyle's comments that the vast majority of Into members would have complied with any measures put in place, Ms Foley accused him of being "incredibly disingenuous".
"In terms of parental leave and unpaid leave schemes being extended in schools, increased subsidies for full-time childcare for essential workers in education, pregnant teachers and SNAs being allowed to work from home on a temporary basis - the public health advice was categorical, unequivocal, and this is public health advice that came from two experts who have worked hand-in-hand with Mr Boyle and the other union leaders.
"When the general society is not doing what general society has been asked to do, in terms of reducing contacts and following public health advice, it puts us in a precarious position."
Mr Boyle denied suggestions the union instructed its members not to go back to the classroom.
"Absolutely not. It is very, very disappointing that the special education is not restarting tomorrow, face-to-face," he added.
"I have an understanding that the vast majority of our members would have complied.
"But after our executive meeting last evening I spoke to 300 members, and the big difference is that the numbers of infection (in the) community are 10 times higher now than they were back in December.
"We were being told that with the level of infections in the community the schools are threatened, and when teachers heard that, it didn't give them confidence, nor the SNAs.
"We certainly hope that with the levels dropping last night, that we will be back for all the children as soon as possible.
"We will work tooth and nail with the department to make sure our schools reopen safely, but there's so much anxiety among everybody."
Ms Foley could not confirm when children with special needs will return to school.
She said the department will continue to work with all the unions, but added: "There has to be good faith.
"It is a matter of deep regret that the unions are not happy at this stage to recognise the essential needs of children with additional needs and not accept public health advice."