The ACT government has promised to rectify any "unintended consequences" from the introduction of the vacancy tax, which resulted in the removal of a longstanding exemption that stopped developers being hit with land tax for two years.

While there is an exemption in the new legislation for land that is under construction, the property becomes liable for land tax as soon as a certificate of occupancy is issued.

That has led buyers of the properties being hit with land tax bills, even though it was applied to their property before their settlement was even finalised.

While the government is exploring ways to patch the legislation and has committed to waivers for affected buyers, it can be revealed Mr Barr's office rejected a plea for help from an affected buyer as recently as last month.

Pensioner and widower Robert Triggs was shocked when he received an overdue notice with 9 per cent compounding interest on a land tax bill last September.

He did not even receive the first notice for the $849.49 bill - that went to his builder, Dino Caruso of Meridian Homes ACT.

Mr Caruso said he'd been hit for land tax bills for up to 12 properties he had developed, of between $900-1000 each. In some cases he paid the bills, as to fight them would hold up the process of settling the property, although he challenged others.

"They've almost got a rope around your neck, there's nothing you can do," Mr Caruso said.

In the meantime, Mr Triggs also questioned the ACT Revenue Office as to why he'd been charged land tax.

Normally the charge applies to land that is not someone's principal place of residence, like an investment property, or land owned by a corporation.

But Mr Triggs lived in his property, and had even been doing so in the week leading up to his settlement as Mr Caruso allowed him to move in early.

However the Revenue Office ruled that he was liable for the charge as the property had been owned by a company at the start of a quarter and he needed to chase the solicitor who did his conveyancing about it.

Mr Triggs sent Mr Caruso a letter of demand for the charge as well, not because he blamed him but because he felt he had no other option.

But in November, Mr Triggs received another overdue notice with more interest, meaning the bill was now $870.76.

Afraid of the charge rising even higher, he paid it but refused to stump up the interest because of the circumstances.

He also approached his local MLA Chris Steel to intervene in the situation.

"I am extremely dissatisfied with the way this has been handled. They have picked on me because they have my address and are using standover tactics to intimidate me into paying," Mr Triggs' letter dated December 29 said.

Mr Steel's office passed the request onto Chief Minister Andrew Barr's office, who responded last month confirming the charge was valid.

"I am advised the ACT Revenue Office has administered all charges in accordance with the legislation," Mr Barr's letter said.

"I hope you understand that the law is being applied consistently to all land tax paying owners and it would be unfair to other taxpayers if I were to intervene in this instance."

Mr Barr's office was approached for comment.

Both Mr Triggs and Mr Caruso have welcomed the government's promise to fix the problematic charge, but have hit out at the opportunistic way it was applied.

"These people are mums and dads moving into a house and they're hit with this land tax, it's disgusting, Mr Caruso said.

"They billed us with no concern whether it was good legislation or not," Mr Triggs said.

Mr Caruso's solicitor Brian Curtis said introducing a three-month exemption from when the certificate of occupancy was issued would solve a lot of issues.

"To me, it's a simple fix," Mr Curtis said.

Any property owner issued with a land tax bill since 1 July 2018 for a property they purchased and moved into without first renting it out should contact the ACT Revenue Office on 6207 0028 or through the ‘Contact us’ page on the Revenue Office website (www.revenue.act.gov.au).