Kent's countryside is likely to come under increasing pressure from developers for house-building because it is cheaper to build on, according to a campaign group.

The Kent branch of the warned parts of the county could see more green field land sacrificed for house-building as the recession continues.

The warning follows the Government's decision to give the go ahead to plans for tens of thousands of new homes to be built across the south east between now and 2026.

Ministers have endorsed the South East Plan, a strategy masterplan for Kent and the region that will determine the extent of house-building up to 2026.

Brian Lloyd, senior planner for the Kent CPRE, said there would be extra pressure in places like Maidstone and Dover - which both pushed for higher housing targets - and Shepway and Thanet.

He said: "A significant proportion of green field land in these places will be needed to meet these targets. One of the big concerns we have in the current climate is that brown field sites are more expensive to develop. There is the real prospect of green field sites coming first for development and brown field sites later on."

But KCC leader Cllr Paul Carter, who now chairs the South East England Councils group, which replaced the regional assembly, cast doubt on whether the targets would be hit.

He said:"These housing numbers seem somewhat hypothetical in the current economic climate. The big challenge in the south east is how we create the environment where house builders have the appetite to take risks and build."

The South East Plan means 32,700 homes will be built each year across the region. But a controversial proposal for the targets to be a minimum figure for each area has been dropped.

Of those, more than 11,080 will be in Maidstone and 9,000 in Tonbridge and Malling. Some 6,000 will be built in Tunbridge Wells. The adoption of the plan means Kent and Medway can expect to see 6,970 homes built each year - the equivalent of nearly 140,000 new homes.

The minister for the South East and Chatham and Aylesford MP Jonathan Shaw said:"If we don't build more houses in the long term older people will have fewer choices and the housing ladder will get even further out of reach leaving the next generation with nowhere to live."