Plans to create thousands of discounted starter homes for first-time buyers must be put into action swiftly to boost the housing supply, experts have said.
Housing Minister Gavin Barwell said 2017 will see the first phase of starter homes being built on brownfield sites in 30 local authority areas around England.
But some commentators have argued the moves will do little to help those on middle and low incomes.
The houses will be available exclusively to first-time buyers aged from 23 to 40 at a discount of at least 20% below market value, with a cap of £450,000 in London and £250,000 outside.
It is understood that the new starter homes will form part of the Government's target to build 400,000 new affordable homes.
Calculations made by housing charity Shelter in 2015 suggested that, to afford a starter home with a 20% discount on the price in 2020, a typical buyer in England would still need an income of £50,000 and a deposit of £40,000. In London, someone would need an income of £77,000 and a deposit of £98,000, based on average lending ratios, according to Shelter's projections.
Roger Harding, director of communications, policy and campaigns at Shelter, said: "Efforts to build more homes are welcome, but these starter homes are only likely to benefit people who are better off and already close to buying. Sadly, they will do little to help the many millions of people on middle and low incomes who need somewhere genuinely affordable to buy or rent long term."
The average house price in October last year was £233,000 in England and £474,000 in London, according to Office for National Statistics (ONS) data.
Figures from the Council of Mortgage Lenders (CML) show first-time buyers typically borrow around three and-a-half times their income to get on the property ladder and put down a deposit of just under 16%. The average first-time buyer is aged 30.
Asked whether there would be a loan-to-income cap for mortgages offered under the initiative, a spokesman for the Department for Communities and Local Government (DCLG) said further details would be announced about the plans "in due course".
Mark Hayward, managing director of the National Association of Estate Agents (NAEA), said: "Today's announcement may feel like a welcome start to the new year, but, as always, we need to see these plans put into swift action.
"The Government has made promise after promise and pledge after pledge to help first-time buyers get on to the housing ladder, but until we see these houses built, we won't hold our breath."
David Hollingworth, spokesman for mortgage broker London and Country, said: "What's crucial is that it builds some momentum and starts delivering properties quickly."
He said recent changes to taxes paid by landlords had led to concerns that rents could be pushed up, making it harder for renters to save for a deposit.
Rachel Springall, a finance expert at website Moneyfacts, said: "There is still so much more that needs to be done to fix the housing crisis.
"First-time buyers are struggling to amass a large enough deposit, particularly if they are paying out a considerable sum on rent each month."
Mr Barwell said: "This Government is committed to building starter homes to help young first-time buyers get on the housing ladder.
"This first wave of partnerships shows the strong local interest to build thousands of starter homes on hundreds of brownfield sites in the coming years.
"One in three councils has expressed an interest to work with us so far."
The first 30 local authorities were selected on the basis of their potential to build the homes quickly and the partnerships have been established under the Government's £1.2 billion Starter Homes Land Fund.
It is hoped the new developments will support wider growth and regeneration, including in some town centres.
The first areas will begin construction later this year along with sites supported by the Homes and Communities Agency.
But shadow housing secretary John Healey said: "These so-called starter homes are a symbol of the Conservative record on housing.
"Ministers launched them in 2014 but will only start to build the first in 2017, promised they'd be affordable for young people when they'll cost up to £450,000, and pledged to build 200,000 by 2020 but no one now believes that's possible."