Research suggests that over half of the people who received money from the government to help them buy a home did not actually need it.
Around 4,000 households in England with combined earnings of £100,000 annually are currently part of the Help to Buy Equity Loan scheme.
Official figures to December 2016 show that the scheme has been used to help 20,000 people that were not first-time buyers.
The initiative, which started in April 2013, is intended to make buying a home more affordable.
However, government ordered research found that 57 per cent of those who used the scheme said they could have afforded their house without utilising the scheme.
Help to Buy was launched by then Chancellor George Osborne to attempt to encourage more housebuilding.
The government will offer a 20 per cent equity loan to buyers of newly-built properties and 40 per cent in London, on properties worth up to £600,000.
The buyers are required to put down a 5 per cent deposit and, after the property has been sold, the government will reclaim the money that was loaned out.
This idea behind this is that, provided the value of the home goes up, the government will make a profit.
Labour’s shadow housing secretary John Healey said: “While the number of younger people who own a first home is in freefall, the number of government-backed affordable homes to buy has fallen by two-thirds since 2010 and badly targeted schemes like Help to Buy are not focused on those who most need a hand up.”
He also accused ministers of handing property developers a “blank cheque”.
“Labour would change that and make helping first-time buyers on ordinary incomes the priority for Help to Buy.”
Gavin Barwell, the housing and planning minister, said: “We’re committed to helping more people find a home of their own with the support of a range of low-cost home ownership products.
“Our Help to Buy Equity Loan scheme continues to make home ownership a reality for thousands of people, especially first-time buyers right across the country.”
The government said it had committed £8.6 billion for the Help to Buy Equity Loan scheme to allow it to run in England until 2021.