A leading environmental group is calling on the government to halt all building on green belt land in Kent.
CPRE has launched an emergency campaign to curb house building
The Campaign to Protect Rural England has launched an emergency campaign to fight proposals which it said could see 100,000 new homes in the next 15 years.
It said that if all the plans and reports due to become public in the next few months get permission, there will be 18% more houses in the county.
But Shelter said the South East housing crisis meant new houses were needed.
A draft housing plan for the South East is to be published on Monday and the South East England Regional Assembly will launch a three-month public consultation period.
The CPRE said this is the final chance for residents of Kent to "prevent the Garden of England becoming an urban sprawl".
It said the government's "hit list" for Kent already includes 20,000 new homes for Ashford, 15,500 for Dartford and 8,300 for Maidstone.
"What we so strongly disagree with is the government and greedy developers tearing up unscathed greenfield countryside because it's cheaper than developing existing brownfield sites," said Hilary Newport, director of CPRE Kent.
"There is a lack of proper strategic thinking about services and infrastructure."
However, housing charity Shelter said Britain's housing crisis was biting hard in the South East.
A record 13,000 homeless households were trapped in emergency accommodation and 60,000 families were in overcrowded conditions.
"Those who argue that we should reduce the level of housing growth need to recognise the case of the current crisis in affordability and supply," said director Adam Sampson.