The London Assembly's environmental lobby has found that a reduction in car parking provision for the Games could save a multitude of green spaces - and businesses.
Green Party members are trying to persuade London mayor Ken Livingstone to look at alternatives to creating 9,000 new car parking spaces for the event.
London Assembly Green Party member Darren Johnson has spoken out against Livingstone's agreement that staff, contractors and Olympic sponsors can travel to the games by private coach and car.
A 15 per cent reduction in parking, the Greens claim, would mean no building on Hackney Marshes and no need to displace 170 businesses on Fish Island.
The party also claims it would save money because the mayor would not have to purchase land, and the costs of the construction of temporary car parks and the restoration of the land afterwards would be avoided.
Johnson said: 'Why are we sacrificing well-used local sports fields, 170 successful local businesses and spending £27 million so that a few Olympic technocrats don't have to walk as far to collect their cars?'