Threshold says it worked to prevent more than 900 households from becoming homeless in the final three months of 2021, which included 1,250 adults and 735 children.
The charity says another 1,800 households were at-risk of homelessness in the same period. That's an increase of 14% on the same period in 2020.
It says more people in rental accommodation were also at risk of homelessness at the end of last year compared to 2020.
Threshold CEO, John Mark McCafferty, said that given the high number of landlords issuing notices for the purposes of sale, there can be no delay in taking action to retain landlords in the rental sector;
"Threshold believes the taxation system has a role to play in retaining small-scale landlords in the private rental sector to protect the current private rental stock. We can see from reports in the last few weeks and months, that landlords continue to leave the market and that looks likely to continue in 2022 - unless action is taken to address this."
Between Q3 and Q4 2021, there was a 30% increase in the number of private renters seeking assistance with poor standards or outstanding repairs in the home.
Problems with damp and mould accounted for just over a third of cases.