Housing charity Threshold has reported a threefold increase in calls during the coronavirus pandemic, as renters face a financial crisis.
The charity is today warning of a potential dramatic rise in homelessness once emergency regulation to protect renters is lifted.
There is currently a ban on rent increases and on evictions.
However, as the first impact of Covid-19 was felt and workers began to lose their jobs, between March 9 and March 30, requests for help rose.
"There's been an unprecedented number of calls and most are very afraid of falling into rent arrears due to a dramatic loss in income," said Threshold chief executive John-Mark McCafferty.
"We're afraid what we're seeing now is minor in comparison to the number of tenants who will need support once the emergency protective measures introduced by the Government last month are lifted.
"We're currently helping many tenants make urgent applications for rent supplement and adjustments to their Housing Assistance Payment.
"We urge tenants facing difficulties to apply for their entitlements immediately and also where possible, to discuss with their landlords the possibility of a rent reduction or deferral, due to the current crisis.
"We do realise this is not a realistic avenue for everyone, however.
"Any renter unsure of how to proceed, should contact Threshold for advice and support."
Threshold chair Aideen Hayden said the crisis posed a real threat to many renters but could also provide an "opportunity to return to a rental market that functions properly, rather than the out-of-control model we have had for a number of years".
The group said a number of tenants, particularly those living in student accommodation, had in some cases, decided to leave, or had been "forced" to leave due to social-isolation measures.
Many are unsure whether deposits will be returned. Those students who paid rent upfront will now need this to be refunded.
Ms Hayden added that many renters now risked falling into arrears and when the ban on terminations is lifted, they could face "difficult situations".
Threshold's helpline is open Monday to Friday, 9am to 9pm on 1800 454454, or at threshold.ie/advice/help.