The Simon Communities has described 2021 as "a year of two halves" due to the moratorium on evictions.
The charity worked with 22,280 people last year, according to its annual report for 2021.
It says initially the moratorium during Covid-19 contributed to a significant decrease in the number of people in homelessness.
However, when it was lifted, there was an increase in homelessness during the second half of the year and this according to its spokesperson Wayne Stanley, has continued to date.
The charity has called on the Government to utilise the latest eviction moratorium wisely.
It was introduced last month and will remain in place until April.
Simon has joined other housing charities in calling for measures to protect people from eviction and to increase the social and affordable housing stock.
The charity provided a total of 119,291 nights of emergency accommodation last year and 5,760 people were supported by Simon's Rough Sleeping and Outreach teams.
More than 1,500 people availed of drug and/or alcohol treatment services, 1,584 people availed of a needle exchange and 616 people accessed health specialist services.
In 2021, the Simon Communities of Ireland generated an income of €1,379,955, almost €150,000 more than in 2020.
Mr Stanley told RTÉ's News at One that social housing should be prioritised for those who are homeless.
He said that more housing was needed, but that housing the homeless needed to take a "health approach" like what was seen during the pandemic.
"It's always very difficult when it comes to public housing because you're dealing with people who are in acute housing need but in the context of the crisis and the trauma that we know homelessness is, we really need to see local authorities stepping up and supporting people out of homelessness," he said.
He said during 2021's ban on evictions there was support to people to come out of homelessness and reduce the numbers of people in homeless, and it was a real "person-centered approach" which was successful for families.
"When the moratorium was lifted society started to open up and we saw that real tightening of the private rental market in particular," Mr Stanley said.
"We saw homelessness start to increase and that increase gathered pace, and we've seen that right up until the end of this year," he added.
He said with the new moratorium on evictions "we have five months basically of breathing space now".
In terms of using that time, he said that it was about increasing capacity and protecting people.
Mr Stanley said provisions are in place for rough sleepers over the coming days as temperatures drop.
He said that the charity was working with local authorities across the country to make sure capacity is there.
He added that this capacity can be makeshift but "there should be a space for everyone who needs it".
He mentioned people in Dublin being able to use an app to identify suitable places, an outreach team in Cork and capacity has increased in the midwest and midlands.