The education systems North and South are still not reaching about 1.1 million adults who had to leave school with little or no qualifications, according to a cross-Border study.
The study describes these adults as the "learning poor" and says there are 800,000 in the Republic, with about 300,000 in Northern Ireland. They have not gone beyond either primary or lower secondary education.
The report by the Armagh based Centre for Cross-Border Studies says the bulk of further and higher-education spending, North and South, is spent on middle-class school-leavers going into third level.
"Since this group is largely middle class, this very large subvention has the effect of reinforcing inequality," says the study.
The study says colleges in both jurisdictions "cater predominantly for middle-class school-leavers", a situation far removed from the vision of lifelong learning.
"Ireland's higher education system is inadequate to achieve such a vision or to meet the needs of people who are not remotely ready to enter higher education," it states.
The study says the Republic has enjoyed unprecedented economic growth and Northern Ireland has been the fastest growing economy in the UK over the last decade.
"If the poor and the learning poor cannot be reached after years of boom, the chances are they will never be helped".
In Northern Ireland there has been "policy drift and stagnation" under direct rule, says the study, and this has created a "huge deficit for the devolved government to make good".
"The Southern system has grown rapidly but, despite much rhetoric, little has been done to tackle the learning deficit among adults," it adds.
It says two features of the Northern system are of particular interest. "While relatively more mature students enter further and higher education than in the Republic, the numbers involved are less than in Britain. Secondly, Northern Ireland adults are less likely to do organised learning than in the UK as a whole".
It says the reasons for this are unclear, but "inhibiting social norms", "an anti-education culture" and the industrial structure of Northern Ireland could play a part.
It acknowledges some progress, especially in some further education colleges, but says many of these remain "forbidding" for adult learners.
"Further education is better geared to the task, but even further education colleges (Northern Ireland) and institutes of technology (in the Republic) are too forbidding for very many of the learning poor".
The recent emphasis on lifelong learning will not itself help disadvantaged groups and special measures to attract them are needed. The report recommends that:
Colleges North and South should set targets for the number of disadvantaged students who are admitted to courses. These targets should be monitored independently.
There should be a joint cross-Border research project into adult learning, especially looking at the potential of communications technology.
A centre focused on family literacy programmes should be set up.
A North-South fund should be set up to encourage co-operation between Northern further education colleges and Southern institutes of technology.
The study - Ireland's Learning Poor: Adult Educational Disadvantage and Cross-Border Co- operation - was written by Mr Mark Morgan, of St Patrick's College, Drumcondra, Dublin, and Mr Paul McGill, former education correspondent of the Belfast Telegraph.
The study is available on the website of the Centre for CrossBorder Studies at www.qub.ac.uk/ccbs