Politicians have criticised independent experts who have overturned housing plans for the South West and increased building numbers in parts of Cornwall.
The panel says 560,000 new houses need to be built by 2026
The South West Regional Assembly spent two years compiling figures for the region's planning blueprint, the Regional Spatial Strategy (RSS).
It then had to be examined by the government-appointed panel of experts.
The panel says more homes are needed in some areas than the RSS says, and it has put up numbers by as much as 80%.
The assembly said the region, from Gloucester to the Isles of Scilly, needed 460,000 new houses within 20 years.
But in a report published on Thursday, the panel said the expected population growth meant the total of homes needed had to be increased to 560,000 new houses to be built by 2026.
There are big variations in numbers across the region. In Plymouth, for example, the figure of 24,500 new dwellings stays the same.
However, the higher level of interest in living in Cornwall means some areas in the county are being made housing hotspots.
In the Kerrier district, the former figure of 8,200 new homes is increased to 14,400; while in the Restormel district the number goes up from 8,600 to 15,700.
Cornwall as a whole would have to accommodate 68,700 new houses by 2026, compared the assembly's estimate of 45,000.
Mike Bawden, the chairman of the Assembly Planning Group, told BBC News that the figures for Cornwall were "mind-boggling" and he could not see how they could be delivered.
Meanwhile Councillor Dick Cole, leader of Cornish political party Mebyon Kernow, called the new figures "ridiculous", and said they would have "a disastrous impact on Cornish communities, our local environment and infrastructure".
The amended planning blueprint is now to be submitted to the Secretary of State for Communities and Local Government, Hazel Blears.
She will hold a three-month consultation on the proposals later in the year before the plan is finalised.