Firm objections have been received from residents in Ringsend, Irishtown, Sandymount and environs to the proposed site for Dublin's incinerator on land beside the Irishtown nature park.
"We are prepared to fight against this," said the Combined Residents Against Incinerator (CRAI) group.
"The consultation process which took place between the Community Interest Group and Dublin City Council was a sham," according to a statement from the group.
Reports earlier in the week that suggested residents had changed from a position of outright opposition to a more measured response were inaccurate, said the group.
By the time the consultation process was complete, most of those actively opposed to incineration had resigned, according to the group, because they were unhappy with Dublin City Council's response.
"We will not have an incinerator in the area," said a spokeswoman for the group, Ms Frances Corr. "We also totally object to another heavy industry, which will cause increased traffic in the area."
The thermal treatment plant is expected to cost €200 million to build and about €600,000 per year to run. It will burn more than 400,000 tonnes of waste a year.
The municipal waste plant will be situated on the Poolbeg site adjoining the newly upgraded sewage treatment works and will not begin burning municipal waste until at least the end of 2006, if it goes ahead.