According to an analysis, around one in four first-time buyers are paying stamp duty as property prices have soared.
The HomeOwners Alliance has called for an urgent review of the tax, which applies in England and Northern Ireland.
The organisation, which drew its conclusions using provisional figures from HM Revenue and Customs (HMRC), said around 26% of first-time buyer transactions were subject to stamp duty in the first quarter of this year.
This compares to roughly one in five (20%) first-time purchase transactions in the fourth quarter of 2017.
After changes introduced from November 2017, first-time buyers paying £300,000 or less for residential property pay no land stamp duty (SDLT).
First-time buyers paying between £300,000 and £500,000 pay SDLT at 5% on the purchase price amount over £300,000, while those buying a property for over £500,000 pay SDLT at normal rates .
Soaring house prices typically push buyers into higher stamp duty brackets, the HomeOwners Alliance said.
Average house prices have hit a string of record highs in recent months, and increases in the Bank of England’s base rates have also led to higher mortgage rates, pushing up borrowing costs.
Paula Higgins, chief executive of HomeOwners Alliance, a property advice website, said: “It is clear that the stamp duty tax needs to be reviewed to ensure that it facilitates rather than hinders first buyers.”
The government recently announced a series of initiatives to support people who aspire to access the property ladder.
Ms Higgins added: “Along with announcing new initiatives to increase home ownership, the Government must increase the existing relief threshold for first-time buyers.
“The relief was introduced in 2017 to reduce initial costs for first-time buyers.
“Fast forward five years and there’s a real risk that first-time buyers will become a tax cash cow, which can’t be fair.”
The Alliance said relief for first-time buyers should be increased from £300,000 to £350,000 “at a minimum”.
He said stamp duty thresholds should also be raised each year based on house prices.
The HomeOwners Alliance said it would like the government to ‘be bold’ and scrap stamp duty entirely for people who buy a house to live in.
Scotland and Wales have different property taxes that apply to property transactions.
A Treasury spokesperson said: ‘We want to help as many people as possible access the housing ladder, which is why we have reduced stamp duty for 90% of first-time buyers who pay it through aid for first-time buyers, as well as investing £10 billion to help unlock more than a million new homes.
“We monitor all taxes.”