A committee of MPs has criticised proposals for a sustainable homes code, accusing it of setting low standards and being afraid to take on the building sector.
The report by the environmental audit committee criticised an announcement by the ODPM that it was strengthening the code, saying the measures did not represent a significant step forward.
It also said the government should prioritise the environmental impact of new homes over other social and economic factors.
Tim Yeo, committee chair, said: "Reliance on developers to gradually begin to do the right thing on a voluntary basis is misplaced and is symptomatic of ODPM's reluctance to take on the building sector."
He said it was essential that the code be made compulsory in the public and private sector.
DEFRA has announced it is raising the lowest standards in the Code for Sustainable Homes. Minimum standards for energy and water efficiency will be above existing Building Regulations.