Indaver Ireland has said it wants to increase the capacity of what is due to be the country's first incinerator near Duleek in Co Meath by a third.
The plant, which secured final statutory approval from the EPA last November, is due to become operational in two years.
However, in a statement tonight, Indaver Ireland said it would seek permission to increase the incinerator's capacity from 150,000 to 200,000 tonnes per year.
The company said this move was in line with the North-East waste management plan, which is devised by the local authorities.
However, the move is likely to anger campaigners who have been opposing the proposal for five years and have threatened to take legal action to Europe.
The Duleek plant is due to burn municipal waste.
A separate plant at Ringaskiddy in Cork, also to be run by Indaver Ireland, is due to burn both municipal and toxic waste.
Tonight's application by Indaver Ireland to increase capacity at the plant near Duleek will have to go to approval to the local authority and will probably end up at An Bord Pleanála.
