But pensioners Robert and Carol Pike are facing the prospect of being forced from their Fisher residence after their sons, to whom they sold the family home in the mid-1990s, were hit with a shock $85,699 bill for land tax liabilities dating back 15 years.

Treasurer Andrew Barr has already agreed to waive $9093 of the debt, but the couple are pleading with the ACT government to wipe the remainder so their children don't have to either sell the home, or dip into their own pockets, to cover the amount.

"This has affected me big time," an emotional Mr Pike, 73, told The Canberra Times from the lounge room of his Clermont Street home.

"This is my house, I have lived here all of my life. I didn't want to see them [children] out of pocket because they have their lives to live. But leave? No, I don't want that. I've been here since day one, this home has a lot of sentimental value."

The family have found themselves in the dire predicament after the parents sold the house to the children in 1994, when Mr Pike was locked in a legal battle with the landlord of his workplace.

The children paid the transaction costs, but the parents have continued to service the mortgage.

The parent lived in the home with the children, before one by one they each moved out.

Under ACT laws, the Pike children would have became liable to pay land tax on the property when the last of them moved out, and the home was no longer their principal place of residence. Owners can be forced to pay penalties if they don't notify the ACT Revenue within 30 days of their property becoming liable for land tax.

But the family's situation was not straightforward. The youngest child moved to the UK, but frequently returned to the Fisher home for months at a time.

In any case, Mr Pike never alerted the ACT Revenue Office because he believed that he "owned" the home the entire time.

In early 2018, the revenue office contacted the children, requesting documents proving who was living in the property and at what time.

On August 21, the revenue office issued the children with a bill for $85,699. The amount included $36,372 in unpaid land tax dating back to 2004-5, as well as $9093 in penalties.

The bill included $40,234 of interest, which was charged at annual rates ranging from 9.72 per cent to 15.75 per cent.

The family objected to bill, but was told the fine was calculated correctly.

Earlier this year, Liberal MLA Mark Parton wrote to Mr Barr requesting that he waive some, or all, of the liability. In his response, seen by The Canberra Times, Mr Barr said while the liability had been calculated correctly, he would waive $9093 of the penalty to "ease some of the financial pressure on the owners and their family".

On Wednesday, Mr Pike said Mr Barr's intervention was inadequate.

"I thought it was pretty ordinary, I thought it was a mongrel act," he said. "I think he should have scrubbed the whole lot. It wasn't intentional [not paying the land tax], we weren't ripping anyone off."

The family is now weighing up two options - either the sons pay off the debt out of their own pocket or they put the house up for sale.

An ACT government spokeswoman did not respond directly to questions about the Pike family's situation, saying it did not comment on "individual tax matters".

But the spokeswoman said the onus was on taxpayers to be aware of their obligations.

"High penalties and interest usually apply if property owners are caught avoiding their tax obligations," she said.

Opposition leader Alistair Coe described the government's treatment of the Pike family as "very cruel'.

"Andrew Barr has no respect for this family, and thousands of others, who are struggling with huge rates and taxes," Mr Coe said.

"The Labor-Greens Government is forcing people out of their homes and out of Canberra."