Banks have reported a surge in calls from mortgage holders seeking information on the three-month payment break.
The banks said they were taking an average of 7,000 calls a day from customers inquiring about it.
All the banks, non-bank lenders and the credit-servicing companies that manage thousands of loans for vulture funds have signed up to the deal, after talks with Finance Minister Paschal Donohoe. The aim is to help those affected financially by Covid-19.
But mortgage experts said the operation of the new scheme had been characterised by confusion and misinformation. David Hall, of the Irish Mortgage Holders Organisation, said the situation was "completely chaotic".
He said the banks had not briefed staff on the scheme, and there was an attempt by some lenders to offer customers interest-only deals instead. He said such an option was cheaper for mortgage providers.
The head of the Banking and Payment Federation admitted there were "teething problems" with the mortgage break plans.
He said the problems should be ironed out by the weekend.