The Revenue Commissioners has extended the deadline to pay the 2012 Household Charge and 2013 Local Property Tax until 5pm on Wednesday 2 April.
The original deadline was today.
Revenue said it had received 10,000 calls this morning from people trying to pay the tax today.
It said: "Property owners seem now to be acting on the fact that the Household Charge, which was initially €100 and increased to €200 last July, will only increase further to €213 by the end of April if it is ignored."
The property tax helpline (1890-200255) is open from 8am to 8pm today and tomorrow, and 8am to 5pm on Wednesday.