In particular, homes in Purbeck, East Dorset and North Cornwall demand almost as big a share of the typical pay packet for local workers under 40 as higher priced homes in the London boroughs of Westminster, Camden and Islington, the research found.
Meanwhile the latest house price survey from property website Rightmove indicated the market had picked up since the end of the war in Iraq.
The study found that prices rose by 1.3% during the past month, following slight price decreases earlier this year.
The study for the Joseph Rowntree Foundation compares local pay with local house prices whereas most affordability studies compare national pay with local house prices.
According to the research, there are 33 local authorities where a small home costs more than five times the average annual income of local working households with earners in their 20s or 30s.
In 19 areas, fewer than one in five young working couples could afford to buy a home.
The analysis challenges any assumption that the crisis is confined to London and the South East
While first-time buyers in the South West are struggling, London still tops the overall league of least affordable areas.
The foundation said there were more than 40 districts in and around London where a key worker couple would find it hard to afford a home.
Professor Steve Wilcox, author of the report, said the research showed how difficult it was for young people to get on the housing ladder, particularly public sector workers.
"These figures provide startling evidence of how the housing affordability crisis is affecting large swathes of southern England.
"The analysis challenges any assumption that the crisis is confined to London and the South East.
"When local incomes are part of the calculation, and we focus on the price of starter homes, it is clear that young working people in many south-western districts, from Cornwall to Dorset, face severe difficulties finding even a small home they can afford."
There was more bad news for first-time buyers from property website Rightmove after its latest survey found house prices picking up again.
Rightmove - which measures the asking prices of properties when they go on the market - found that prices rose 1.3% from mid-April to mid-May as the end of the war in Iraq lifted confidence.
Prices have now risen by 4.7% over the first five months of the year, equivalent to an annual rise of 11.6%. This is still much lower than last year's rise of more than 25%.
Like most of the recent property surveys, Rightmove found prices rising more strongly in the North of England.
Values climbed by 4.4% in the North, 3.6% in the North West and by 3.3% in Yorkshire, but fell by 1% in the Greater London area.
"The springtime surge in home buying has been late this year as people had their minds elsewhere," said Ed Williams, managing director of Rightmove.
"Now our agents are starting to see more activity and more transactions are being done."