More than half of households in Northern Ireland are existing on incomes below £300 (€445.80) per week, government statistics reveal.
The levels of poverty are contained in a new report, Households Below Average Income, Northern Ireland, 2005-06, released by the Department for Social Development.
Anti-poverty campaigners and Sinn Féin said the figures underscored the need for government action to counter disadvantage, especially among children.
The Northern Ireland Council for Voluntary Action said the findings were "deeply worrying" and it claimed that more than half of all children were living in families on low incomes.
"The proportion of children living in poor homes has risen from 51 per cent to 56 per cent in the last two years, despite government plans to eradicate child poverty. The local figure of 56 per cent compares poorly with the child poverty figure of 49 per cent in Britain," it said in a statement. The council also said that poverty among older people was also on the rise with the proportion of pensioner households with low incomes up from 52 per cent in 2002-03 to 59 per cent.
"Northern Ireland clearly needs to be far more ambitious in its plans to tackle poverty," said NICVA chief executive Séamus McAleavey. "This must be a top priority for the Executive and Assembly.
"The anti-poverty strategy needs to be taken off the shelf and we need clear policies and targets if we are to achieve our target to end poverty."
Alex Tennant, Save the Children's head of policy and research, said: "The estimate of 100,000 children in poverty in Northern Ireland was a matter of grave concern, requiring urgent action."
Sinn Féin said:"It is time for the Executive to deliver a genuine anti-poverty strategy that can make a real difference to our communities."