Government policies are pushing home-ownership out of the reach of ordinary families, with prices likely to rocket to 13 times the average wage by 2020 if the Conservatives win next year's election, Labour has claimed.
At current trends, the cost of an average home could reach £359,000 by the end of the next Parliament, requiring a £72,000 deposit, according to shadow housing minister Emma Reynolds.
Ms Reynolds also accused the Government of failing to build enough homes, claiming that 1.3 million new properties are needed to fill the housing gap and unveiling figures suggesting that Labour councils are building 300 homes a year more than Tory authorities.
And she challenged the traditional Conservative claim to be the "party of home ownership", pointing out that owner-occupation is lower under the coalition than in any year of the last Labour administration.
But ministers said her assault was "not credible", insisting the rate of house-building has risen to its highest since 2007 and accusing the former Labour government of a "truly appalling" record on housing.
Housing minister Brandon Lewis hailed figures showing that almost 40,000 households have now bought homes through the Government's Help to Buy scheme, which supports people struggling to raise a deposit on a home by offering equity loans or mortgage guarantees to cover up to 20% of the value of properties worth up to £600,000. Of those, 32,000 involved the purchase of newly-built homes.
Quarterly figures showed that more than 80% of the purchases were by first-time buyers, creating what Mr Lewis called "a new generation of home-owners" and contributing to a 34% increase in private housebuilding during the first year of the scheme.
Ms Reynolds said that Help to Buy was boosting demand without increasing supply, fuelling the surge in house prices.
In a speech in Nottingham, she said: "While the Tories say the housing market is back on track, the truth is they've presided over the lowest level of house building since the 1920s.
"Fewer affordable homes were built last year than the last year of the Labour Government. The fewest number of social homes built since records began."
She added: "Government ministers like to talk about Help to Buy. We support help for first-time buyers, but the Government simply haven't understood that boosting demand without boosting supply risks pushing prices out of reach of the very families and young people who are struggling to get on the housing ladder.
" The Tories claim to be the party of home ownership. But the truth is, home ownership today is at its lowest point in any year since 1987... For every year of the last Labour Government, home ownership was higher than it is now.
"They pay lip service to aspiration, but what's the point in talking about it if you're not willing to make it happen? The only way to ensure more people can buy their own home is to build many more homes."
Labour analysis suggests its councils are committed to building 862 homes a year, compared with 508 by Tory councils and 393 by Lib Dems, she said.
Leader Ed Miliband tweeted a picture of a Labour poster from the 1945 election hanging on his office wall, promising "a non-stop drive to provide a good home for every family". He said: "It's still relevant today. Once again we need a non-stop drive to provide a good home for every family. Labour will get 200,000 homes a year built by 2020."
Mr Lewis said: "This speech from Labour just isn't credible. Here's one fact they won't tell you - under the last government Britain was building fewer homes than at any time since the 1920s. Labour's record on housing was truly appalling.
"By contrast, housebuilding is now at its highest for a number of years and we have already delivered over 445,000 new homes, including 200,000 affordable homes.
"Labour would cut housebuilding through taxes and red tape - and it's hard working taxpayers who would pay the price for this failure."
New figures from the Department for Communities and Local Government showed that 27,167 equity loans for new-build homes have been taken up under Help to Buy in the first 15 months of the scheme, while 5,388 newly-built homes were bought under NewBuy. Some 7,313 sales were completed over six months with mortgage guarantees, which can be used with older homes.
The average price of properties purchased under the equity loan scheme was £208,000 and £151,000 under the mortgage guarantee. The highest number of equity loan sales were in Wiltshire with 469, Leeds with 457 and Central Bedfordshire with 427, while Milton Keynes, Peterborough, Bradford, Manchester, Country Durham, Bedford, and Birmingham each racked up more than 300.
Mr Lewis said: "Hard-working families are getting the homes they want, while house-building has increased to its highest level since 2007.
"It's no accident that, since the start of the scheme, private house-building has shot up by a third and continues to climb. Developers are increasing their output, and taking on new workers at the fastest rate since records began."
Alex Hilton, director of campaign group Generation Rent, said the figures showed equity loans were having a limited impact in areas where homes are most expensive, like London.
"These numbers prove that Help to Buy is not delivering where homes are most needed, which is where there are jobs," said Mr Hilton. "And yet the publicity around Help to Buy continues to prop up a dysfunctional housing market that, like an addict, snorts ever more cash from the pockets of renters and from taxpayers in the form of Housing Benefit."