The final round of consultation before plans for the Norwich Western Link are lodged has been delayed - because the results of ecological surveys have yet to be fully analysed.
And opponents of the £198m road hope it could spell problems for the controversial scheme.
Norfolk County Council wants to build the 3.8-mile road to connect the A1067 Fakenham Road and the Northern Distributor Road to the A47 to the west of Norwich.
An application is due to be lodged with County Hall's own planning committee early next year.
However, a final round of consultation, due to take place in the autumn, has not happened.
Martin Wilby, cabinet member for highways, transport and infrastructure at Norfolk County Council, said: “The project team are considering the findings of this year’s ecology surveys that will feed into our proposals for the Norwich Western Link.
"We’ll update people as soon as we can on when the consultation will get under way.”
The council said it was too soon to say if it would delay the planning submission.
Ecologist Dr Charlotte Packman, from Wild Wings Ecology, has identified a super-colony of barbastelle bats in the area, prompting Norfolk Wildlife Trust to call on the government to grant special status to protect them.
Green county councillor Jamie Osborn said: "We thought this was going to happen and have been asking for their legal advice around the road, which the council has not given us.
"The whole way it has been run has been secretive and chaotic and I think it is coming off the rails."
Emma Corlett, Labour county councillor, said: "This scheme is going to face hurdles at every stage, because there are so many glaringly obvious problems, given the environmental and wildlife considerations.
"My prediction is this will delay the planning application, but the council has failed to make the risk register about that available, despite councillors asking for it."
A number of businesses have backed the road, as have MPs, the New Anglia Local Enterprise Partnership and Norfolk Chambers of Commerce.
But it is opposed by groups such as Norfolk Rivers Trust, the Campaign To Protect Rural England and The Bat Conservation Trust.
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