Increasing the supply of land available for construction would do little to bring down house prices, the Campaign to Protect Rural England has said.
The study says the amount of free land does not affect house prices
According to a study for the CPRE, rising house prices are a reflection of bigger incomes and mortgage loans.
The research tracked house prices, completions and housing land supply over periods of 10 years or more.
It suggests that proposals to relax planning controls could "unleash a new wave of urban sprawl" in the country.
The government is currently considering proposals that would see minor developments such as conservatories no longer needing planning permission, where there is judged to be little impact on neighbours.
There are also considerations for replacing public inquiries into major schemes with an independent commission.
CPRE policy director Neil Sinden said: "Evidence uncovered by this study suggests the government needs to rethink its planning policies for housing.
"The relaxation of planning controls, which it is pursuing, will encourage builders to use more greenfield land rather than redevelop more difficult urban sites.
"This could unleash a new wave of urban sprawl across the countryside and deprive our towns and cities of continued investment in regeneration."
According to the study, most of the local authorities it looked at had large land supplies, enough for more than 10 years' demand. All had either constant or rising amounts of land available.
John Slaughter from the Home Builders Federation told the BBC that it was a "myth" to suggest the industry had an agenda to dismantle the greenbelt.
Construction firms had adapted "very effectively" to increased building on brownfield land in recent years but in future may in some areas need to consider greenfield development due to shortage of land.
"There is, in principle, plenty of land there," he said.
"The key issue is actually bringing it flexibly to the planning system so it has got permission to build on."
Prime Minister Gordon Brown has announced that three million new homes would be built in England by 2020 - up 250,000 from the government's previous plan.
The Department for Communities and Local Government said a package of proposals to support more new housing would be outlined in its Green Paper next week.
"It is little wonder that house prices are going up whilst demand continues to outstrip supply," a spokesperson said.
"We will continue to prioritise brownfield land and retain the robust protections for the Green Belt."