Tight deadlines, a lack of resources for special education and concerns about class sizes are among issues teaching unions and opposition parties believe could scupper hopes of reopening schools on time next month.
While the government's roadmap to reopen 4,000 schools has been welcomed, trade unions have expressed fears there is not enough time to roll out plans before doors reopen.
However, Education Minister Norma Foley has reiterated that she believes schools will reopen on time.
Under the plan, an extra 1,000 teachers will be sourced and building works completed so children can go back to classes safely.
While there still will be risks, potential infections have been planned for and some €375m is being put aside to get school classes set up, to hire more teachers and train staff.
Criticising the government's plan, Sinn Féin said that government could have announced its reopening plan for schools much sooner.
Sinn Féin’s Donnacha Ó Laoghaire said: "We always knew there was going to be a need for additional staff, we always knew there was going to be need for additional space, we always knew there was going to be need for investment in additional hygiene measures," he said.
"A lot of that could have been handed down to schools, and they could have been well underway on the process of recruiting, seeking additional space, or planning adjustments to their building."
Labour's Aodhan O'Riordain said a “magic wand” is needed to get everything done in a few weeks.
Both the Teachers' Union of Ireland and the Association of Secondary Teachers in Ireland also have doubts about the timeline.
TUI General Secretary John MacGabhann said not all schools will be ready to reopen fully by August 31 and that a “staggered” intake of students may be required.
He told RTÉ there may be delays finding contractors to carry out works for which €75m is being made available.
ASTI President Deirdre Mac Donald said the timeframe for changes is too tight. It would be a challenge to recruit 1,080 teachers by then, she said.
Education Minister Norma Foley said when the schools reopen younger children will be taught in bubbles or "pods" with a metre between them and that a common sense approach will apply to younger children having to social distance.
Asked if home-schooling is over for parents, Ms Foley said: "Absolutely. The plan that we unveiled yesterday puts significant resources into schools so they can re-open in a safe manner that is sustainable and does not compromise education standards.
"Parents and students and society wants schools to re-open fully open. This is back to school as normal for our school community."
Ms Foley said panels of substitute teachers will be drawn up so that substitute teachers can work in more than one school if and when the need arises.
"Substitute panels for primary schools have been successfully piloted over the past year so now, substitute panels are going to be rolled out nationwide and teachers will have one-year contracts."