Mole Valley District Council is consulting on plans to move boundaries to allow the building of up to 2,200 homes over the next 13 years.
The Campaign to Protect Rural England (CPRE) has now started a campaign called Save Surrey's Countryside.
The council said there was insufficient land available in built-up areas for new homes and other development.
Andy Smith, from the Surrey branch of the CPRE, said the group was concerned about development around places like Guildford, Reigate and Leatherhead.
"These areas have been built and built over the years," he said.
"All these towns have expanded to such an extent we have to say enough is enough."
Mole Valley District Council said it was is looking at green belt land around the area's towns and larger villages to see if there was potential for development.
John Northcott, the councillor responsible for planning, said: "This consultation document does not identify sites for development or suggest land that could be taken out of the green belt.
"Instead it sets out a process for reviewing the green belt boundary and we will use the findings of the consultation to help shape our future work."
A campaign has begun to fight a proposal to remove land from the green belt in Surrey to build housing.