The State paid landlords nearly €436m under a social-housing scheme last year.
That is an increase of over €81m on 2019.
The Housing Assistance Payment (HAP) is a form of social housing support provided by all local authorities.
Under the scheme, part of a tenants rent is paid by the State - which makes payments to landlords every month.
According to Freedom of Information (FOI) figures obtained by Newstalk, the exchequer paid landlords nearly €355m under the scheme in 2019.
This rose by more than one-fifth last year, to nearly €436m.
In the final quarter of last year, nearly 60,000 tenants were availing of the scheme - up almost 7,300 on the previous year.
Dublin's four local authorities paid out €212m under the scheme last year, which is nearly half of the country's total amount.
While €45m was paid in Cork, and nearly €26m in Louth.
John-Mark McCafferty, chief executive of the housing charity Threshold, says the scheme is needed.
"It's necessary for the time being and for the next number of years into the medium term, while we continue to build social housing.
"The Housing Assistance Payment needs to be with us for some time yet, and it does allow many people to access private rented housing.
"But it's not a silver bullet, and it doesn't address all of the issues in relation to people's housing need".