Stamp duty was cut for first-time buyers at the end of November, giving savings of up to £5,000.
It means that eight out of 10 people buying their first home now don’t pay the tax.
More than nine out of 10 are liable for a lower stamp duty bill, after the changes in the Autumn Budget.
First-time buyers pay no levy on a home up to £300,000 and only on £200,000 for properties costing up to £500,000.
The Prime Minister said: “I have made it my personal mission to build the homes this country needs so we can restore the dream of home ownership for people up and down the UK.
“In the autumn we set out ambitious plans to fix the broken housing market and make sure young people have the same opportunities as their parents’ generation to own their own home.”
It’s expected that around 1m people will benefit from the changes.
Stamp duty cut ‘raises house prices’
However, the changes will simply push up house prices, according to Labour’s shadow housing secretary John Healey.
He said: “The number of young home-owners is in free-fall but under the Tories the number of new low-cost homes for first-time buyers has halved and not a single one of the 200,000 ‘starter homes’ promised has been built.
“After almost eight years of Conservative failure on housing, homelessness has doubled, home-ownership has fallen to a 30-year low and the number of new social rented homes is at the lowest level since records began.
“It’s clear Theresa May has no plan to fix the country’s housing crisis.”