St Vincent de Paul also says it expects a high level of calls this year
Children's charity Barnardos says it saw a big increase in people seeking its services last year.
According to preliminary figures, the charity supported more than 14,869 children and families in 2017 - compared with 14,163 in 2016.
Fergus Finlay, Barnardos CEO, says: "Every year Barnardos works with hundreds of families facing a wide spectrum of challenges.
"In 2017 we worked with more families and children than ever before. Homelessness, lack of access to vital health services, family discord, parental addiction and/or mental health difficulties, bereavement and loss are among the many reasons why families come to Barnardos.
"We will continue this work through 2018, as well as continuing to challenge society where it fails them.
"Every child is born with unlimited potential, we need to protect, nourish and unleash this potential and we will all be the richer for it."
Barnardos head of advocacy, June Tinsley, adds: "In 2017 we witnessed the escalation of two critical issues which are putting many families under extreme stress - homelessness and medical waiting lists.
"3,333 children were living in emergency accommodation at the end of November 2017.
"Hundreds, potentially thousands more are living in inappropriate and crowded accommodation with extended family and friends.
"The steady rise in the number of homeless children throughout 2017 has made it clear that the Government’s approach is not sufficient to tackle this ever-worsening crisis."
Ms Tinsley says: "The time has come for the Government to turn words into action and make a firm commitment to children in Ireland – a commitment to safeguard their childhood and their potential.
"2018 must see the Government investing in quality public services when and where they are needed most, services that support families and protect children."
Meanwhile the Society of St Vincent de Paul (SVP) says it expects a high level of calls for help in 2018, despite the improving economic forecast for the year.
Last year it says it received close to 130,000 calls for help, and spent an estimated €30m on providing direct assistance to those in need.
In a new year statement, SVP national president Kieran Stafford says: "While we would hope for a universal improvement in the ability of all Irish people to benefit from the overall economic improvements the reality is that it is unlikely to happen.
"There are four main conditions that exist that drive people to seek SVP help.
"They are the level of consistent poverty; the high number in employment struggling on low pay and inconsistent working hours; the many families with children living in emergency accommodation and the gap between those who can easily avail of third level education and those from more disadvantaged areas."
The latest CSO figures released just before Christmas show that the level of consistent poverty has only marginally improved between 2015 and 2016, falling from 8.7% to 8.3%.
SVP says while unemployment figures are reducing, "this masks the reality that many of those now employed are in poorly paid or insecure employment and consequently struggle to meet essential bills."
It says almost one-quarter of those experiencing deprivation are at work, demonstrating that employment does not always guarantee a decent standard of living.
"Without social transfers such as Jobseekers Allowance, Pensions and Child Benefit 44.9% of the population would be living below the poverty line", it adds.