Nearly nine out of ten people in the Midlands believe the green belt should be protected from development, according to new research.
New housing and urban sprawl was highlighted by the public as the most significant threat facing the green belt but there were also concerns about airport expansion and other development.
The worries were raised in a poll conducted for the Campaign to Protect Rural England marking the 50th anniversary of the Government circular instructing councils to look at setting up green belts.
The poll, which was carried out by MORI, interviewed 931 people aged 15 and above across the region.
Of those questioned, 85 per cent of people in the Midlands said the green belt should remain protected and undeveloped.
The West Midlands region covers 13,000 square kilometres, with green belt accounting for 2,679 sq km - virtually unchanged since 2001.
But while the area has remained about the same, the location of protected sites has shifted - a policy that critics said was not preventing urban expansion.
Gerald Kells, the regional policy officer for the CPRE, said: "People think that by moving the green belt out, it is doing its job. It isn't."
The West Midlands population increased by an estimated 90,000 to about 5,319,900 between 1991 and 2003 - the latest year for which figures are available.
The growth has fuelled demand for housing and increased pressure for development in rural areas. Mr Kells said that pressure had to be resisted if alternatives were available.
"Green belt land should only be freed up for housing development in exceptional circumstances, when there is no land available in the towns to build on," he said.
"The Government has suggested that if house prices are too high, then more houses can be built to reduce prices. However, this won't work.
"Traditionally, if you give them the opportunity, housing developers would much rather build in 'uncontaminated' areas, like the proposed plans for Dickens Heath, than build in the towns."
The CPRE is also asking people who care about the future of the green belt to fill in a postcard or online form stating why it is so important to them. So far they have collected around 800, which they plan to deliver to the Government later this month.
Anyone wishing to fill in a postcard can get theirs at www.cpre.org.uk, or by calling 0207 981 2869.