New figures from the CSO show the number of primary school-aged children is projected to increase by up to 100,000 by 2021.
The rise represents an increase of around 20% on the 2011 figure of 502,000.
The secondary school-aged population of 13-18 year olds is projected to increase by between 105,700 and 116,800 by 2026, depending on the assumption used.
The fastest increases are expected between 2021 and 2026. This represents increases of between 31% and 34% on the 2011 figure of 342,400.
The number of people aged between 65 and 80 is also projected to increase very significantly, from its current level of 532,000 to 860,000 by 2026.
It is expected to be close to 1.4m by 2046.
The number of people aged 80 and over is predicted to rise even more dramatically, increasing from 128,000 to 470,000 over the next 33 years.
Life expectancy for males is expected to rise from 77.9 in 2010 to 85.1 in 2046. The figure for females is expected to rise from 82.7 years to 88.5 years.
Research Professor with the ESRI, Alan Barrett has described the figures as ”really striking”.
Speaking on RTÉ's News at One, Mr Barrett said while it would mean a lot of building and recruitment of teachers, we also need to look beyond these figures because the population peak could pass and we need to prepare for that as well.
He said figures projected that there would be many more people living over the age of 65 and while that is a good news story, there are costs attached to this and implications for pensions and healthcare.
He said for every person over the age of 65 at the moment, there are five people working and paying taxes. By 2046, he said, there will only be two people working for every person over the age of 65.
He said the Government is aware of this problem, and there are moves afoot to offset some of the difficulties including extending out the age of eligibilty for the State pension .
It is the view of the ESRI that there will be a funding need in areas like health and social welfare.