Revenue has extended the deadline for Local Property Tax filings by three days, to Wednesday 12th November.
It comes as the tax authority says it is seeing "strong engagement" from property owners in recent days, leading to its helpline being overwhelmed this morning.
Property owners are required to file updated valuations for their homes to ensure they are in the correct tax bracket in the coming years.
The deadline for submissions had originally been set for today, however Revenue has now extended this to 5.30pm on Wednesday, 12th November.
Revenue said it had so far received filings for around 1.4 million properties - 140,000 of which have been submitted since Wednesday.
It said its helpline continues to experience high demand, which has led many calls to go unanswered.
Revenue said it is currently receiving around 7,000 calls each day, but its monitoring indicates that 4,000 callers were unable to get through this morning alone.
It has also received around 10,000 pieces of correspondence - through online messaging and paper returns - which are in the process of being worked through.
It has advised property owners to file their return online at revenue.ie/lpt - or via Revenue's MyAccount, ROS or LPT portal.
Once logged in customers will be asked to determine the valuation band of their property as of 1 November 2025, and submit their return.
Revenue said advice on how to work out the value of a property - including an interactive valuation tool which gives an estimate based on location - is available on its website.
Customers do not have to pay the tax at this stage, but they are asked to set out their preferred method of payment - which can include a full upfront payment, monthly direct debit or deduction from wages.
Those who do wish to contact Revenue by phone are able to do so on 01 738 3626.
