More than half of private tenants who contacted Threshold last year were at risk of entering homelessness, according to its latest annual report.
Some 19,947 households were assisted by the housing charity last year, 10,729 of which were deemed to be at risk of entering homelessness.
The report says that the charity prevented 4,807 adults and 2,916 children from entering homelessness in 2021.
Despite those efforts, 209 households entered homelessness and 72 were forced to stay with family and friends when their tenancy could not be protected.
The outcome is "unknown" for the remaining clients, according to the report.
It says that while efforts were made to follow up with all clients, Threshold advisers were not always able to make contact.
Tenancy terminations was the biggest issue that faced private tenants for the fifth consecutive year - 29% of queries related to termination of tenancy.
Of those who entered homelessness, 69% had received a notice of termination from their landlord.
The majority of those notices were valid and could not be challenged according to the housing charity, which resulted in renters entering homelessness because they could not find alternative housing.
Threshold has pointed out that there was a decline in the number of households prevented from entering homelessness in 2020 and 2021, due in part, to the moratoria on evictions.
This prevented landlords from acting on or issuing notices of terminations for much of 2020 and the first quarter of 2021.
While many households remained at risk of homelessness in this time, the outcomes of their cases were delayed as the moratorium pushed out their eviction dates.
Just under 6,000 at risk cases were carried over into 2022, according to the report.
Threshold says its advisers encountered a larger level of queries concerning standards and repairs compared to previous years, with 10% of private tenants seeking advice on their accommodation.
This may be a result of delays in carrying out repairs during the public health restrictions, throughout parts of 2020 and 2021.
Threshold Chief Executive John-Mark McCafferty noted that of the almost 20,000 contacts made with the charity last year, almost 12,000 were first time contacts.
"Our advisers supported this stark number of households with over 22,000 issues, meaning that some households faced two separate challenges in their private rental accommodation in the space of 12 months and required Threshold's advice or help to deal with these," he said.
"Our work is critical in supporting householders to remain in their homes, during what is a deepening housing crisis for many of those who rent and feel vulnerable."
In 2021, Threshold advisers represented 255 households at the Residential Tenancies Board and assisted 291 households to submit disputes
The charity has also noted that legislation introduced to limit the amount for a deposit requested by a landlord to the equivalent of one month's rent last year was of "particular significance" to students who are renting accommodation.
It identified 121 private renters who had been discriminated against, as they were seeking the Housing Assistance Payment and while in many cases, the Threshold adviser was able to assist the client to resolve the situation with the landlord - in some cases, the client was forced to find another home.