The Government has clashed with one of Oxfordshire's leading politicians over the number of new homes needed to tackle the growing shortage of affordable housing.

Housing Minister Yvette Cooper branded the South East England Regional Assembly (Seera), chaired by Oxfordshire County Council leader Keith Mitchell, as "bonkers" for proposing cuts in the number of new homes built each year.

Under the draft South East Plan, drawn up by Seera, Oxfordshire would aim to provide an average of 2,360 extra homes per year over the next two decades - a mix of new build and conversions.

This is significantly fewer than the 3,538 new homes which were provided across the county in 2005/6.

The plan, currently under consideration by an independent panel of experts, which may still be amended, would see South East England as a whole provide 28,900 per year on average until 2026.

This would represent a slight improvement on the current Government target of 28,050 per year. But it would fall shy of the 33,309 the region succeeded in building in 2005/6.

Ms Cooper, speaking in the Commons, said: "New housing is now at its highest rate for 20 years but we need to go further, given the serious pressures on affordability.

"Regional assemblies also need to do more. That is made harder in the South East because of the approach of the South East England regional assembly, which is arguing, unfortunately, for cuts in the level of house building.

"We have an ageing and growing population, with more people living alone. We need to go further and build more homes for the next generation. It is not fair on them if we do not. Frankly, the approach of the Conservatives in the South East is bonkers."

However, the Department for Communities and Local Government would not set a figure on what Ms Cooper believed should be built in Oxfordshire.

Andrew Smith, Labour MP for Oxford East, backed the minister's comments and said: "The figure Seera is working to doesn't meet the demand and need in central Oxfordshire. I want that overturned and replaced with more realistic numbers, so people who desperately need housing in Oxfordshire can get it."

Mr Mitchell stressed that the regional homes target contained in the draft South East Plan was higher than the Government target it would replace.

He said: "There is no evidence that simply building more houses makes it more affordable to buy a home. House building in the South East has risen 20 per cent in the past five years alone but prices have soared.

"So while over the next 20 years we are planning for an additional 578,000 houses, we want 200,000 to be socially rented or shared equity.

"And we are pressing the Government to commit to the investment in infrastructure needed to support all this new development."