Deputy Prime Minister John Prescott has called for a dramatic change in the rate of home building to meet demand and rein in house price inflation.
Most of the Green Belt would not be affected by new building plans
Mr Prescott, who has overall control of housing policy, suggested that planning regulations may have to be revised.
Although most of the Green Belt will be protected, some previously undeveloped sites would need to be used, he said.
He told the Observer that pressure groups "must face up to reality" on the need to build where homes are wanted.
He said that rural groups always opposed plans to build on greenfield sites even when they were the most suitable places, such as when near road or railway links.
"What are they suggesting? That I say to people in the South East they catch the train to Hull where they are knocking down houses? They must face up to reality," he said.
The construction programme could involve building as many as 260,000 homes per year for a decade.
Mr Prescott added that there was a need to ensure sustainability in housing as well as more moderate increases in prices.
"The most important thing is to get the numbers up, and to get houses that people can afford," he said.
"We inherited a growing crisis in housing - prices... roaring ahead faster than earnings, and people's ability to pay."
But shadow local government secretary Caroline Spelman later criticised Mr Prescott's proposals.
She warned that shortage of affordable homes could not be tackled by building on greenfield sites.
"I don't agree on the where or the how or the what," she told Sky News's Sunday with Adam Boulton programme.
"I certainly feel that John Prescott is wrong when he says the most sensible thing to do is build on Green Belt. I am not convinced. I don't think there is any proof of that."