Half of the people experiencing significant numeracy problems in the Republic have completed their Leaving Certificate exams according to new research published at the launch of National Adult Literacy Awareness week.
Social researcher John Sweeney has found that of the 700,000 people found to have significant deficits in an OECD numeracy test three years ago, 13% had completed third level courses.
He said in 2013 the OECD had also found that four out of ten people with significant literacy difficulties are at work.
He said there is no incentive for employers to up-skill workers in low-paid jobs and urged the education sector to pay more attention to the problem.
The Awareness Week promotes the availability of free courses in over one hundred centres throughout the country for people experiencing difficulties reading, writing or doing maths.
It was launched in Dublin by President Michael D Higgins.
President Higgins said a culture which accepts that citizens will drop out of its education system unable to read or write, and become disengaged and disenfranchised at an early age cannot call itself a true republic.
Dr Sweeney's research shows that of those in Ireland found to be at or below level one in the OECD's PIAAC survey, 23% had primary education or less; 27% had completed the lower secondary cycle; 24% had completed the Leaving Certificate, 13% had studied Post-Second-Level courses and 13% had studied at tertiary level.
The survey was also undertaken in 23 other countries but Dr Sweeney is the first researcher to have broken down the Irish results in such detail.
The National Adult Literacy Agency, which organises the Awareness Week, says that 50,000 people are attending literacy and numeracy courses nationwide, which are provided free by local education and training boards.
It says the 2013 OECD survey estimated that one in six Irish adults has problems with even the simplest literacy task such as reading instructions on a bottle of aspirin while one in four people find it difficult to do simple maths.
It added that, as low skilled jobs become less available, people without a qualification are at the greatest risk of unemployment and already form the greatest group who are unemployed.
NALA says individuals who do not have a basic education also have poorer health and in general lower life expectancy and life chances.
NALA's Director Inez Bailey said that sometimes people are very worried about returning to education and hide their difficulties with reading and writing from their friends and family.
However, she cautioned, this does not have to be the case and NALA would encourage anyone to call us on 1800 20 20 65 to find out about all the learning options available to them.