Campaigners warned too much greenfield land with permission for housing could hamper efforts to regenerate brownfield sites

Too much greenfield land with planning permission for housing developments could hamper efforts to regenerate brownfield sites, conservation campaigners have warned.

In some areas the viability of developing brownfield sites falls if there is competition from a ready supply of greenfield land nearby, a report from the Campaign to Protect Rural England (CPRE) showed.

The CPRE said the findings of its report had wide significance as councils sought land to accommodate the national target of three million new homes by 2020.

The conservation organisation's senior planner, Kate Gordon, said some local areas which had relied on brownfield sites to meet their housing needs may face pressure to allocate greenfield for development - in turn threatening regeneration of local brownfield land.

"We urge councils contemplating large-scale greenfield land releases not to proceed unless they are satisfied these will not harm prospects for redevelopment and regeneration.

"Tremendous potential still exists to make better use of brownfield opportunities and reap the long-term rewards in terms of urban renewal."

But she said: "Great care needs to be taken over the scale, location and timing of greenfield land release."

A Department for Communities and Local Government spokeswoman said: "The clear priority for development will remain previously-developed or brownfield land.

"The latest provisional estimates for 2008 show that 78% of homes were built on brownfield land, up from 56% in 1997. Targets are being exceeded but councils will need to continue to prioritise development away from greenfield sites."