The roll-out of the revised version of Part L of the Building Regulations could be delayed for six months. The new regulations are due to come into force on 1 October and will set more stringent energy performance targets for buildings.
But fears are growing that the Part L update may be delayed by the Government's anti red-tape committee.
The house building industry is also having trouble getting hold of workable computer calculation software and has called for more time.
The Government's new Reducing Regulation Committee, chaired by Vince Cable, has been tasked with running the rule over all new regulations to weed out ineffective or costly measures.
The revisions to part L fall under its remit and must be assessed but it has not yet sat to consider the changes and make an assessment.
If the October window is missed the Government is likely to opt to introduce regulations on 6 April.
According to a report in Building magazine the Home Builders Federation has also written to Andrew Stunnell, the Building Regulations minister calling for a delay.
House builders want the timetable pushed back to allow them time to run through new compliance software used to calculate energy performance.
Changes needed to SAP - Standard Assessment Procedure for the Energy Rating of Dwellings - were published earlier in the year. But these still need to be incorporated into calculation software offered by different providers, then tested and approved.
John Slaughter, director of public affairs at the HBF, said: "If we don't have the final version of SAP, then people can't specify final designs. This makes a material cost impact and can affect the value of sites."
A spokesman for the Department for Communities and Local Government said the intention was to introduce regulations in October as planned but they would have to be vetted by the regulation committee.
