Stroud College plans Stratford Court sports complex
Plans for a sports facility in Stroud have gone out to public consultation.
Stroud College wants to lease land at Stratford Court to build a £4.8m floodlit all weather pitch, running circuit and changing rooms.
The land is owned by Stroud District Council and is currently being used as an open space.
But campaigners opposed to the plans are concerned it would "formalise" the site's use and "ruin the area".
Save Our Green Open Spaces spokesman Ron Morton said the area had been used for all sorts of activities for the past 50 years.
"Under the plan there'd be specific area for dog walkers and for picnicking," he said.
"This infers they'd be barred from using it for the informal recreational use... and that's what enhances the public wellbeing."
But Kevin Hamblin, principal of Stroud College, said the last thing it wanted to do was to displace the current activity.
He said by building the facility it would allow more people to use the space.
"Because we are building the facilities for use in the daytime we will give them over to the local clubs in the evening," he said.
"We want more children to play sports... and for the clubs to use the facilities which have been already been paid for by the taxpayer."
Independent councillor for Stroud Central, Andy Read, said many regarded Stratford Court as a village green and warned of a "public outcry" if there was not proper consultation.
"The council needs to ensure if anything comes forward that the community is consulted from the very start and that they are engaged in this process," Mr Read said.
Stroud District Council said no planning application has so far been received.