Queensland's property sector is calling for a scheme to tax investors on their entire Australian portfolio to be scrapped as at least one other state reviews the legality of the move.
Real Estate Institute of Queensland chief executive Antonia Mercorella warned the land tax revisions earmarked to come into effect in 2023 were untested and may be unconstitutional.
"We are now being inundated with calls by investors, by real estate businesses, and of course by the general community in disbelief," Ms Mercorella said.
"Make no mistake; this is an unprecedented move. There is no other state or territory in this country that treats land tax in this way."
NSW is questioning the move's constitutionality, which will see interstate investors slugged thousands of dollars.
NSW Finance Minister Damien Tudehope described it as a blatant tax grab.
"I have been informed by Revenue NSW that it has not received any requests for data sharing in relation to the recent Queensland land tax amendments," Mr Tudhope told AAP.
"I am seeking advice on the constitutionality of such a regime.
"This sort of tax grab is exactly what you would expect from a Labor government - they never miss an opportunity to raise taxes."
However, Queensland treasurer Cameron Dick said the issue had been raised with interstate and territory counterparts.
"We work across the country with the Australian Taxation Office. All of the heads of the state revenue offices work together collaboratively on tax measures now," Mr Dick told reporters.
"So we don't anticipate any problems working with other states on this."
Previously, only land held in Queensland was taxed. Under the changes, investors with interstate holdings will pay more tax.
The government expects the change to rake in $20 million a year from 2023/24 and impact about 10,000 landholders.
Queensland Opposition Leader David Crisafulli claimed the tax could result in rent hikes of up to $100 a week for people amid an ongoing cost of living crisis.
"This is a tax that will affect everyday Queenslanders. In fact, it will affect the most vulnerable Queenslanders," he told reporters.
"Queenslanders will go home and have to talk about the rising costs of their household budget with inflation rates going up ... the last thing they need is for investors to put up their rent at a time when they are struggling to make ends meet."
Liberal National Party treasury spokesman David Janetzki said the land tax changes were unworkable.
He said recent budget estimates hearings revealed Queensland Treasury had no idea who the tax would affect, how much revenue would be raised, or how it would be collected.
"We now see the practical implications ... we are now seeing that people are deeply concerned about the regulatory uncertainty here in Queensland," Mr Janetzki told reporters.
"We are seeing investors saying that they are looking to withdraw their property from them, that they will increase their rents, and that will have a real day-to-day impact on Queenslanders living with a cost of living crisis."