The Revenue Commissioners have decided to extend the online property tax filing deadline until 8pm tomorrow evening.
It is due to what they call "the unprecedented volume" of people filing their property tax return today.
They have received up to 10,000 property tax returns per hour online.
Revenue said that they have received approximately 30,000 calls to their helpline today alone, totalling around 450,000 calls to date, while around 8,000 people have tried to file their property tax return over the phone today.