A waste incinerator scheme in Norfolk has been thrown into "chaos" over government concerns about opposition to the scheme, it has been claimed.
Environment Secretary Caroline Spelman said she wanted more information before releasing £169m for the King's Lynn plant.
Norfolk County Council said the minister's stance could jeopardise the project.
A judicial review is under way into the award of the £600m plant contract.
In a letter to the county council, Mrs Spelman said she was "concerned by the large volume of objections".
She said she wanted more evidence about the waste management plans before deciding whether to back the project with £169m of "waste infrastructure credits".
Bill Borrett, cabinet member for environment and waste at the Conservative county council, said: "After years of carefully following the criteria laid down, this apparent late moving of the goalposts has surprised and dismayed us.
"Worse, we are concerned it may lose Norfolk people as a whole a government grant worth a staggering £169m.
"By her action, she has apparently thrown a carefully followed process into chaos."
Elizabeth Truss, Conservative MP for South West Norfolk, backed the minister for seeking more information about the project.
"I think that's right because the people of west Norfolk are not happy with the proposals as they currently stand," she said.
Earlier this year, campaigners against the incinerator served notice on the county council that they were seeking a judicial review.
They claim there were "irregularities" with the way the authority awarded the contract.
The county council said it had "complete confidence in the process".
It appointed Cory Wheelabrator to build and run the plant.
The facility would process about 260,000 tonnes of rubbish every year.
The council said it would also save £8m a year that would otherwise be spent sending rubbish to landfill sites.
The new facility would burn the waste and produce electricity.