A Rocha UK has branded the reforms as regressive, suggesting they bring environmental policy 'back to the Thatcher era'.
Developers will automatically be given permission to build on suitable disused industrial land under major reforms to boost housebuilding, George Osborne has announced.
More derelict brownfield plots could also be seized for development through beefed up compulsory purchase powers under the plan unveiled by the Chancellor.
Major infrastructure projects that include new housing will be fast tracked and Whitehall will step in if councils fail to act to meet local housing demands.
However, the government has said there is no need to build on green belt land, despite environmentalist suggesting it may be the more radical option, while some developers believe the amount of brown field land is too limited to properly address the housing crisis.
"The challenge is the terms are misleading, greenfield doesn't necessarily mean it's of significant value to the wildlife or the community, it just means that ... it is a space that is green and can include some low-grade agricultural land," said spokesman Andy Lester.
'Brown field' affectively means it's had an alternative use before, and therefore it's being put back into constructive use, but our wildlife is getting squeezed out.
So, our road verges now ironically are probably the best places for wild flowers ... and our 'brown field' sites can sometimes be fantastic for wildlife", added Mr Lester.
So treating it with such a broad brush approach is dangerous and also suggesting that somehow by protecting the 'green field' site we're protecting peoples interests is misleading.
The Church of England is currently debating whether to dump fossil fuels from its £6.1bn fund at its final General Synod of 2015, taking place in York