Teachers, parents and principals have welcomed the Government's roadmap to reopening schools - but there are concerns the €375m budget will "not be sufficient".
Unions are also calling for more clarity on substitute teaching as there are fears there will not be enough staff in the event of a second wave of coronavirus.
Principals have voiced concern that they will be bogged down in administrative work over the next five weeks.
The National Association of Principals and Deputy Principals (NAPD) said that while the time period to implement the plan is short, it wanted to assure parents and students that they will do everything they can to ensure schools open in August and September, in line with public health advice.
However, it called on the Government to ensure school principals are afforded the time to do this.
"Work in the next five weeks cannot be hampered by increased paperwork and administrative requirements, something that school principals are already overwhelmed by," said Clive Byrne, director of NAPD.
Schools and teachers say they are now faced with an enormous challenge which has to be overcome in a very short period of time.
Martin Marjoram, president of the Teachers' Union of Ireland (TUI), described it as a "massively complex operation".
"Should the initial budget set out today not be sufficient in this regard, additional resources must immediately be made available if and when required," he said.
Meanwhile, the Irish National Teachers Organisation (INTO) has called for further clarity on substitute cover.
"We recognise that there will be areas that are not covered by a supply panel of substitute teachers and these schools will need further guidance on substitute arrangements," an INTO spokesperson said.
"In addition, we sought agreement on the provision of substitute cover for certain other absences, we still await clarity on these.
"Our members have asked for illustrated classroom templates to inform how they layout their classrooms in line with the prevailing public health advice. We have been working to safely reopen with the largest primary school classes in the European Union, and class sizes must urgently be addressed by this Government."
The Association of Secondary Teachers, Ireland (ASTI) said it is concerned the investment and resources being made available may be insufficient.
"The measures that are being put in place must be sustained for as long as the threat of the pandemic remains," said ASTI president Deirdre Mac Donald.
"The health and safety of the whole school community is an imperative."