Dogged opposition to the biggest house building programme since the 1950s is putting West Midlands local authorities on a collision course with the Government.

Ministers have made it clear that the region's councils must plan for a minimum 471,000 new dwellings by 2026.

The unprecedented growth is required to address demographic changes, in particular the rise in single-person households, and is part of a national house building strategy devised by Deputy Prime Minister John Prescott and backed by the Local Government Secretary, Ruth Kelly.

Members of the West Midlands Regional Planning Partnership believe Government targets are over-inflated, unachievable and will put enormous pressure on the green belt and the countryside.

There are also concerns that construction on such a scale will increase emissions of greenhouse gases, put more vehicles on the roads and conflict with sustainability policies.

The Partnership, meeting in Birmingham yesterday, proposed an alternative option that would see no more than 410,000 new homes built between 2006 and 2026.

It is doubtful whether the compromise will be accepted by Whitehall.

The Government Office for the West Midlands, in a letter to the Partnership, warned: "The allocation, phasing and location of housing is part of the wider process of developing the best sustainable solution for the region and should not be treated as an excuse for not rising to the challenge posed by the household projections or the needs of the region.

"Failure to provide adequate housing will only exacerbate the current problems of affordability, overcrowding and homelessness which impact adversely on wider social and economic issues."

New housing will be concentrated on the major urban areas, including the Birmingham conurbation and Coventry. Several towns where "a balance of jobs and services can be best provided", have been earmarked. They include Hereford, Rugby, Shrewsbury, Telford and Worcester.

Most councillors doubt that the Government targets will ever be achieved.

Peter Douglas Osborn said Ministers were "barking at the moon" if they thought the West Midlands would be able to deliver 471,000 new dwellings.

The new-build figure in Birmingham would be 80,000 over 20 years, a target that was unachievable and would inevitably mean encroaching into the green belt, he said.

Coun Douglas Osborn (Con Birmingham) added: "It took us three years to build 2,500 homes in the Jewellery Quarter, and we were impressed by that. What we are being asked to do now is simply horrendous and we have to face up to that fact."

Robert Rowden, a member of Worcester City Council, warned that the Government expected local authorities to plan for thousands of new homes without providing any funding for new roads, schools, drainage and other infrastructure. "How are people in these houses going to move around? How are they going to travel?"

Solihull borough councillor Ian Courts called for greater discretion to allow local authorities that wanted housing growth in their area to take a higher proportion of the target figure.

Coun Courts said there had to be a question mark over the ability of the construction industry to build so many new properties without a drop in standards.