Originally, Gordon Brown planned hundreds of thousands of homes in 10 "carbon neutral" communities but the proposals had to be scaled back because of legal disputes.
Housing Minister John Healey said: "The proposals can raise strong opinions, but climate change threatens us all.
"With our commitment to the eco-towns we are taking steps to meet this challenge and help build more affordable housing."
But Shadow housing minister Grant Shapps attacked the plans as an "eco-con".
"Many of these schemes are unsustainable, unviable and unpopular," he said. "But Gordon Brown wants to impose them from Whitehall irrespective of local opinion.
"All the low-flush toilets in world can’t make dumping a housing estate on green fields somehow eco-friendly."
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