112,000 fewer 15-34-year-olds were employed in the last three months of last year - compared with the same period in 2019.
ESRI research shows the impact of the pandemic has hit younger people hardest with many working within the hospitality and entertainment sectors.
Earnings have also stagnated in recent years, with workers in their early 20s earning less in the 2010s than they did in the 1990s.
ESRI Economist Barra Roantree says the issue is also linked to the 2008 financial crisis:
"There's also a lingering effect of the financial crisis - so while the labour market had almost entirely healed for older workers that weren't the case for younger workers - so people who were in the 1980s and 90s were leaving school and college were coming into a market still not fully back to where it was at - so as a result, they were earning less."
