The Local Property Tax helpline has received more than 80,000 calls in the last three days alone.
It comes as a Revenue is to extend the deadline for property owners to file their LPT returns until 5.00pm on Wednesday.
But it says returns for over one million properties have already been filled, with 93% of those being done online.
Overall, some 1.8 million returns are expected to be received by the new deadline.
Katie Clair is head of Revenue's LPT branch. She told Lunchtime Live people are trying to do the right thing.
"In the last three days alone, returns for over 250,000 properties have been filled.
"So it's become very clear to us, from the volume of activity that we're experiencing, that the vast majority of property owners want to do the right thing and they want to file their LPT return ahead of the deadline.
"We've also had over 80,000 calls to the LPT helpline, and 15,000 items of correspondence received, in the last three days alone.
"So we're conscious that there is concern and there's some worry for property owners who maybe have not have had a reason to engage with Revenue on a day-to-day basis.
"We just want to reassure taxpayers that we will support them in meeting their LPT obligations - and the decision has been taken to extend the deadline to 5.00 on Wednesday next, the 10th of November."
But she says there have been some issues with their website.
"We had a very minor technical issue after 8.00 last night, and that was fixed in about an hour and we haven't had an issues on that since.
"The questions that we are receiving, the phone calls that we are receiving from people - in some circumstances people are looking for reassurance, they're looking to ensure that what they are doing in terms of technique or obligations is correct."
She says homeowners have to do three things.
"What we want to reassure property owners is that they are requited to do three things to determine the current market value of their properties, so that they can decide which valuation band it falls into.
"To submit the valuation to Revenue in their LPT return by the extended deadline... and when submitting that return, to identify how they are going to pay".
Ms Clair says one of the most common questions is around letters from Revenue.
"People are concerned that they haven't received a letter - we issued 1.4 million letters, and 900,000 of those were issued in paper.
"But the remainder were issued electronically; so some of those letters have gone to either your 'My Account' or your ROS inbox.
"So we would ask property owners to check those two platforms, just to make sure that the letter isn't in there already".
She says the second common question is around valuation, a tool for which can be accessed online.
"Our interactive valuation map considers location, average price range, date of build and other factors.
"When somebody logs in to submit their LPT return, they will a valuation already set - defaulted, let's say - on their LPT portal."
But she says this can be changed by the user.
"The valuation guides are based on averages, so they don't necessarily provide an accurate valuation for your property.
"So if your honest assessment differs from the value returned on the online guide, you should reflect that in your valuation.
"You can change it yourself, you can self-correct it".
However if property owners change the band with supporting documents, they should keep these.
"They could look to - for example - Daft.ie, MyHome.ie... you have the Property Price Register or property pages in newspapers.
"Any sources that they've used just to retain them".