More than 500,000 new homes are needed over the next 20 years
Devon and Cornwall is dramatically failing to reach its home building targets, according to a housing body.
The South West Housing Initiative (SWHI) said about 14,000 homes were built last year - 22% fewer than 2008 and 5,000 short of the average target.
The regional body, representing home builders and housing professionals, said demand in the greater South West is for 25,000 new households each year.
It warned the lack of affordable housing threatened the local economy.
Richard Kitson, SWHI chairman, said if young people cannot afford to live in the South West, there is a real risk is they will move out of the area.
"We're particularly concerned because if the economy is to come out of recession we want a strong recovery," Mr Kitson said.
"We need to make sure business and industry can find people who have got homes and can live and work in the area. Fundamentally, people want a roof over their heads and a home of their own.
"Clearly if we're not building enough homes, then the problem of affordability grows and young people may leave the region."
Chris Wood, an estate agent in Helston, Cornwall, said a big concern is that although the housing market appears to be picking up, the supply will never meet the demand in the South West.
"We have a growing population generally and the number of households in increasing because of divorce and people choosing to live alone," he said. "We're always going to have a property shortage of some sort."
In its 2010 report, the SWHI said that homes in the South West cost nearly 12 times the annual average earnings - making it one of the least affordable regions in Britain.
The Regional Spatial Strategy for the South West (RSSSW) has said more than half a million new homes are needed to meet official predictions for the next 20 years, but last September the government said it was re-evaluating that strategy to ensure it was the "most sustainable way forward".