Over 280,000 houses need to be built in the West Midlands by 2020 if they are to become more affordable, a think-tank has said.
The National Housing and Planning Advice Unit has claimed that up to 3.48 million new homes may have to be built in the whole of England.
It is advising the Government not to focus on the property market downturn but to continue to think about long-term needs.
Stephen Nickell, chairman of the NHPAU, said: "We are at the beginning of a period of adjustment in the housing market.
"And while inevitably there is now a focus on the gloomy short-term prospects and some uncertainty arising from this, for the sake of communities and future generations it is vital that planners and decision makers keep an eye on the medium and long-term.
"This is about acting now in advance of the next upturn. It is about ensuring that plans for new homes to be finalised by 2011 cater effectively for people's legitimate expectations and aspirations."
Unsurprisingly, it is southern regions where the NHPAU thinks the greatest number of new homes needs to be built, with it advising that between 486,200 and 622,500 additional properties should be added to the South East by 2020, as well as between 428,500 and 529,100 in London and up to 486,300 in the East.
The North East needs the fewest new homes to be built in order for property to become more affordable at between 87,800 and 97,300, while NHPAU advises that up to 283,700 properties should be built in the West Midlands.
The group stressed that the figures were only advice to the Government and should not be seen as regional housebuilding targets.
The Communities and Local Government team will consider the recommendations when it finalises its own formal guidance to regional planning authorities in its Regional Spatial Strategy reviews, which are due to be completed by 2011.