Rent in Cornwall rose 7% over the past year, new figures show.
Pro-growth campaign group Britain Remade said millions of young people will be paying "ever-rising" rents and "locked out" of buying homes until enough new houses are delivered.
Provisional figures from the Office for National Statistics show the average private rent in Cornwall reached £987 per month in the year to September – up 7% from £922 a year prior.
It was also up 30% from an estimated £757 per month five years ago.
Valuation Office Agency rent officers collect prices from a variety of sources, including landlords and letting agents, with the aim to collect data on approximately 10% of the market.
Across the South West, the average rent was £1,200 – rising 5% from the year before.
Bristol had the highest rental cost in the region at £1,791 per month, while the lowest was in Torridge at £776.
Sam Richards, chief executive of Britain Remade, said: "It is increasingly looking like the Government will miss its target to build 1.5 million homes by the end of this Parliament.
"Until we build the homes we need, millions of young people will be locked out of home ownership and stuck paying ever-rising rents."
Nathan Emerson, chief executive of Propertymark, said: "We are about to witness some of the biggest evolutions in over thirty years within the rental sector, with the Renters' Rights Bill across England and the Housing (Scotland) Bill.
"Both will make fundamental changes to how landlords operate and are aimed at strengthening consumer rights concerning standards.
"Across the forthcoming decade, it is essential that all eyes are turned to encouraging long-term investment in the rental sector to keep up with increased demand and population growth."
In September, the average private rent in Great Britain was £1,366 per month. This was £71, or 5%, higher than 12 months ago.
Including estimates for Northern Ireland, ONS head of housing market indices Aimee North said: "UK annual private rents inflation has eased for the ninth consecutive month, and annual growth has slowed for all countries across the UK."
The figures also show the different costs for various homes in Cornwall, from £679 for a one-bed property to £1,488 for a home with four or more bedrooms in September.
Among the property types in the area:
- A detached house cost £1,265 to rent per month
- A semi-detached cost £1,053 per month
- A terraced house was £1,019 per month
- And a flat or maisonette was £802 a month