House prices cost nearly eight times earnings on average in England and Wales last year, according to official figures.
The Office for National Statistics (ONS) said in 2017, full-time employees could typically expect to spend around 7.8 times their annual earnings on purchasing a home in England and Wales. The affordability ratio increased from 7.6 in 2016.
The change was driven largely by the decreasing housing affordability in England, with no significant change in Wales between 2016 and 2017, the report said.
In 2017, full-time employees in England and Wales could typically expect to spend 9.7 times their average annual earnings on buying a newly-built property and 7.6 times their annual earnings on an existing property, according to the ONS.
Kensington and Chelsea in London was the least affordable area to buy a property in England and Wales, with house prices being 40.7 times earnings.
Copeland, in the North West of England, was the most affordable local authority in 2017, with house prices being 2.7 times earnings.
Owen Woodley, chief executive, financial services at the Post Office, said: "Despite a slowdown in house price growth over the past year, a range of factors have continued to place pressure on would-be buyers' purchasing power - especially those looking to take their first step on the ladder."
Polly Neate, chief executive of Shelter, said: "The homes we're building are nearly 10 times people's incomes."
Separate Government figures released on Thursday showed 69,000 first-time buyers have so far benefited from the recent abolition of stamp duty on properties priced at under £300,000.
Over the next five years, it is estimated the policy will help over one million people getting onto the housing ladder.
And over 1.1 million accounts have now been opened with the Help to Buy Isa, offering Government bonuses of up to £3,000.