Queensland's property sector is calling for a plans to tax investors on their entire Australian portfolios to be scrapped.
The state government has passed laws to tax investors on their total holdings, including interstate, from June 2023.
Previously only land held in Queensland was taxed, and 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.
Real Estate Institute of Queensland chief executive Antonia Mercorella is calling for the "unprecedented" tax hikes to be scrapped, saying investors will pass on the costs to renters.
"It will increase rents," she told reporters in Brisbane.
"It will also have an impact on commercial entities who operate businesses in Queensland, and it may well impact employment levels.
"We are calling on the state government to urgently repeal this land tax regime."
Ms Mercorella criticised the government for allowing only 10 days of consultation on the changes.
She said the tax hike could be unconstitutional and the full impact was still unclear.
"We are now being inundated with calls by investors, by real estate businesses, and of course by the general community in disbelief," she 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."
The REIQ boss warned that investors could sell off their Queensland holdings to avoid paying more tax, and interstate investors will be deterred.
Queensland Opposition Leader David Crisafulli claimed the tax could result in rent hikes of up to $100 a week for people amid an ongoing a 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."
