Almost one in six of the Republic's adults who are living in poverty have a job, according to a new survey from Social Justice Ireland.
The organisation urged the Government to refund tax credits to families who do not earn enough to benefit fully from them.
SJI calculated that the number living in poverty has increased by 120,000 since the beginning of the recession and that almost one in six of the adults in this category are what are known as "the working poor".
The SJI paper found that almost one in five children is living in poverty.
The paper encourages the Government to adopt poverty-reduction targets for this and other vulnerable groups such as lone parents, jobless households, people with disabilities and those in rented social housing.
SJI said the top-earning one-tenth of households received 24% of the State's total disposable income while the bottom one-tenth received only 3%.
It also said that most weekly social assistance rates paid to single people are €14.21 below the poverty line.
SJI director Fr Seán Healy said poverty is growing despite the fact that the poverty line is falling and the "bottom line is that the vulnerable have not been protected by the budgets in recent years".