Plans for a new bridge over the River Thames in Surrey, which has been 20 years in discussion, could be delayed by at least four years, says a report.
The new crossing will be built upstream from the existing bridges
A timetable from Surrey County Council shows the earliest a bridge linking Shepperton and Walton-on-Thames could be completed is the end of 2011.
Residents have expressed concern about the design of Walton Bridge, which will replace two temporary bridges.
The Walton Bridge Campaign said there had not been enough consultation.
Its chairman, Ronald Segal, said over the past two decades the council had twice put up "environmentally horrendous proposals" for a replacement bridge, both of which were ruled out.
He said campaigners wanted a plain flat bridge which didn't "obtrude in a local environment of considerable beauty", rather than the current plan for a structure "the height of an 11-storey building".
But council spokesman Mick Avery said all the issues had been debated at length over the years, and a firm decision on the design for an arch bridge had been agreed.
He said all that remained was for developers to redesign the junction with Walton Lane at Coway Sale, so that it took up less land.
"We hopefully have a fairly simple task."
Mr Avery added that there had been "enormous consultation, and there would be more".