Single carriageway sections of A11 and A47 will not be dualled before 2010.
The projects were not in Transport Minister David Jamieson's list of roads in the region to be given a share of £700m over the next three years.
Norfolk County Council's transport spokesman Adrian Gunson said it was "a real slap in the face" that the projects had been omitted.
They include the Attleborough bypass and Thetford to Fiveways on the A11 and the A47 Blofield to North Burlingham.
Work had been due to start on the A11 schemes in 2006/7.
Because the schemes were not included on the government's list a Regional Transport and Infrastructure Board will now decide on a priority order.
Norfolk County Council said this would lead to serious delays and the schemes could not start until 2008/9 at the earliest.
Mr Gunson, cabinet member for planning and transportation at the county council. added: "This looks like a device to delay the dualling of trunk roads in Norfolk.
"The government has not consulted at all with our local authorities so this is a real slap in the face for all councillors, local people and businesses... who have campaigned for the remaining sections of the A11 in Norfolk to be dualled.
"It means that in this decade there will be no further dualling of any trunk road in Norfolk and we will remain the only city in England separated from London by single carriageway roads," he added.