The opening of two new multi-denominational schools has been postponed until next Monday because of a delay in getting certification for the temporary buildings that they will occupy.
The schools were all supposed to open or reopen last Monday.
Last week this was postponed until today. However patron body Educate Together says the Department of Education has informed them of another deferral, and the schools will not now open until next Monday.
Earlier, it was thought that four schools were affected, however it has since been clarified by Educate Together that just two schools were affected.
Educate Together has said it shares the disappointment and frustration of parents.
It has criticised the delay to the Government construction projects.
In a statement issued today it says neither it nor the schools' managers or principals have had any role or responsibility for the schools' delivery. It says the delay has been caused by delays in completing building work in time to get the certification necessary to enable a building to open.
The patron body has also criticised what it calls a lack of communication from the Department of Education, which "has exacerbated the stress caused by the delays".
Another new Educate Together school, Dublin North East ET Secondary School, has been forced to open in alternative temporary premises because the temporary premises planned for the school, on the grounds of another school, are not yet ready.
Educate Together says it has consistently raised concerns with Department of Education officials around the short timeframes involved in announcing and subsequently opening new schools.
It says it has also raised concerns with the department on delays in the scheduling of works and in the timing of planning applications.
The new primary schools affected are: Dublin 13 ETNS, and Killester/Raheny/Clontarf ETNS.
This is the latest problem to beset school buildings this year, as a number of other schools have had their return delayed by ongoing structural remediation works to their faulty Western Building Systems constructed buildings.
In a number of other cases children have returned to find their schools shrouded in scaffolding and fencing as a precautionary protective measure until permanent remediation works can take place.
One WBS school building at Ardgillan Community College in Dublin's Balbriggan remains permanently closed because of safety concerns.
Educate Together, in its statement, has said it recognises and shares the deep frustration and inconvenience faced by families, staff and the wider school communities involved.
It says the situation is particularly disappointing for Junior Infant children and their families.
Last week the organisation expressed concern that all 12 of its new schools opening this year were doing so in temporary accommodation.
It said it was seeking formal commitments that arrangements around accommodation for nine new schools due to open next September were properly planned and fit for purpose.