It follows a public demonstration in Stroud which saw hundreds of people protest against plans for a £500m incinerator near Gloucester.
Developers Urbaser Balfour Beatty (UBB) had successfully appealed against a council decision to turn down plans for the Javelin Park site.
The Labour county councillors have called for an extraordinary meeting of the county council in order to hold a vote on cancelling the contract.
The town council officially objected to the incinerator and town mayor Amanda Moriarty gave evidence at the inquiry.
Now the town councillors are writing a letter of support for the extraordinary meeting.
They are also writing to the Secretary of State, Eric Pickles, expressing their disapproval of the decision.
“This decision flies in the face of localism,” said the town’s deputy mayor, John Marjoram. “It has completely ignored that fact that the community did not want this incinerator.”
Opponents highlighted issues including the size and cost of the 30-acre site and the environmental impact.
In 2013 county councillors voted to turn down plans for the facility, a decision which went against a recommendation by the council’s own planners that it be approved.
Gloucestershire County Council had already signed a contract with UBB to build the energy-from-waste plant.
The company appealed to the Secretary of State’s office and following a planning inquiry the government inspector decided the energy-from-waste plant could go ahead.