The owner, Karen Paxton, runs a small recruiting agency from her Fyshwick office, which was adjoined with a second block before she bought it, land that was once home to a railway easement.

But Ms Paxton was sent a valuation notice of $61,000 in January 2017 for the easement block, up from a previous valuation of $21,000, which sent her rates bill up significantly from year to year. It sent her on a six-month mission to find out why.

Ms Paxton was one of many businesses operating from Fyshwick, Mitchell and Hume who have told an ACT Legislative Assembly inquiry about some large increases in their valuations in recent years which have increased their rates bills.

But, after six months of research including freedom of information requests and going to the ACT Ombudsman, she told the inquiry she still had no answer from the territory's revenue office as to why the valuation was increased.

Ms Paxton bought the property - a unit-titled block with the adjoining "sitting-duck" block - 13 years ago, but unlike all the other blocks along the old railway easement, it was not amalgamated into the main block.

Instead, she said planners took years, from when the lease was issued for the block to when the previous owners bought it, for it to be attached to the unit title, but not amalgamated as part of the same lease.

Ms Paxton said she had not been bothered by the rates bills or the separate titling, until the increase in 2017 seemed to interpret the block as commercial property, despite the only allowed development of it being for a surface car park or storage.

"It seems like it's a forgotten block, but then someone in the valuation office was looking around the area in 2016 and spied it, and decided, well there's a block we can triple the value on," she said.

Despite trying to object to the 2017 valuation, she was told it was too late after the initial two-month objection period, and invited to object the following year, which she did.

Ms Paxton said since then she had been forced to apply for the documents underpinning the decision under freedom of information legislation, and the government could not find any reasons for the increase.

She said she had also discovered there were two other increased valuations of blocks along the old railway easement, but they had been increased by only between 14 and 21 per cent that year, nothing close to the 305 per cent increase she had experienced.

Ms Paxton told the committee she wanted the government to amalgamate the two blocks and pay back about $30,000 in rates she had paid on the separately titled block.

Other property owners also vented their frustrations to the committee.

Sharon Cvetanoski and Arthur Lagos of Phillip Traders Marketplace said the value of their land had been dragged up by the purchase of the nearby First Choice Liquor for $9 million, which was then turned into a Maserati dealership.

The properties are considered like-for-like, as the Marketplace's crown lease also allows for a car dealership to be built on the land.

As the site has "never been and will never be a car yard", Ms Cvetanoski and Mr Lagos said it was unfair to compare the two, especially as the Maserati dealership was selling $400,000 cars.

"There's only so much retailers like the Salvation Army [one of their tenants] can raise the cost of their products by," Ms Cvetanoski said.

The Marketplace even went so far as to lodge a development application to reduce the floor area permitted in their crown lease by 50 per cent, hoping it would reduce their bill. It went down by 5 per cent.

“This case will go to ACAT,” Mr Lagos said.

Scott Molloy, who is now paying rates of $33,000 on his commercial property in Hume, said: "the only thing that’s holding commercial property in the ACT together at the moment is that the inflation rate is so low that you can only get 2.5 per cent in the bank".

"If we use one of the units at Hume, round it off and say it’s worth $300,000 and it’s returning $20,000 a year, if inflation goes up and interest rates go up then investors will want 10 per cent so that property that’s returning $20,000 won’t be worth $300,000 anymore, it will be worth $200,000," Mr Molloy said.

"It will drop by 50 per cent in value for a 3 per cent rise in inflation and interest rates. And that’s extremely scary for commercial property. Commercial is all about numbers and how they stack up."

Fyshwick property owner Barry Faux said: “if there’s any recession in the ACT this is all going to steamroll into disaster."

The hearing was also not without controversy.

Proceedings were suspended twice after Labor politician Bec Cody kept asking witnesses if they were members of political parties. The committee chair, Liberal Vicki Dunne, ruled the question out of order.