Councils in Surrey and Sussex have expressed their disappointment that road schemes have been put on hold as part of the government spending review.
The new Walton Bridge over the River Thames in Surrey and the Bexhill to Hastings link road in East Sussex are among the projects affected.
The coalition government has told the Department for Transport (DfT) to make savings of £683m by March 2011.
East Sussex and Surrey councils said the schemes were a priority for them.
The £30m Walton Bridge, was to have replaced two "temporary" bridges at Walton and Shepperton.
The project has faced numerous delays but was approved by the previous government in 2008.
Surrey County Council was granted a compulsory purchase order for the land last year and was awaiting final confirmation of funding.
Council leader Andrew Povey said he would be "hugely disappointed" if the bridge could not be built.
"Major infrastructure projects are essential to helping the economy through the downturn," he said.
"With Surrey's roads carrying twice the national average traffic flow and the county being a powerhouse of the national economy, this scheme is a high priority for us and should be viewed similarly in Whitehall."
The Bexhill to Hastings link road was the subject of a planning inquiry last November.
Provisional funding was agreed in October by the previous government.
Councillor Matthew Lock said East Sussex County Council was disappointed but not surprised it had been delayed.
"Having said that, the Bexhill to Hastings link road remains one of the county council's key priorities," he said.
"We believe it is vital to the economic regeneration of the area and wider South East. We will, therefore, continue to make the strongest possible case for funding."
The DfT's spending review is expected to take about eight months.
Transport Secretary Philip Hammond said in a statement: "The Government has made clear its most urgent priority is to tackle the UK's record budget deficit, in order to restore confidence in the economy and support the recovery.
"Only once the government's spending review has been concluded will the Department for Transport be in a position to identify those major investments that can be supported."