The new targets, agreed in conjunction with the EU-IMF troika, also stipulate the number level of "concluded solutions" on the banks' books must reach 35 per cent by the same date.
There are just under 100,000 Irish mortgage accounts more than 90 days behind in their repayments.
The State's six main mortgage lenders - AIB, Bank of Ireland, Permanent TSB, Ulster Bank, ACC Bank and KBC Bank - now have until the middle of next year to put debt arrangements in place for 75,000 of them.
The banks can write down debt, reschedule the loan, put a new payment plan such as a split mortgage in place or repossess the home.
"In line with the EU-IMF programme, the Central Bank has now set its expectations for the banks for end-June 2014 and requires sustainable solutions offered to customers to reach 75 per cent of over 90-day arrears and for concluded solutions to reach 35 per cent by that date," the bank said in a statement.