Fianna Fail is calling for a review of inheritance tax.
In the last four years, the number of people liable for the tax has increased by more than a third, as thresholds have decreased.
Inheritance tax must be paid on properties worth over €225,750.
On a house worth €500,000, they would face a bill of €90,000.
Senator Mary White is hosting a meeting on the issue tonight in Dublin.
She said that it is deeply unfair.
"They have to write the cheque fast becaue they have to pay it within the year that they're bequethed by October 31," said Senator White.
"What happens then in many cases is that the child, whatever age they may be, or an adult they're in a chronic state of bereevement over their parent and they have to either borrow the money or sell the house, and that is not right."