Motorists wanting to drive between Wyesham and the rest of the town, or up into the Forest and along the Wye Valley, will have to cross at either Huntsham Bridge in Goodrich or Bigsweir Bridge between 8pm and 6am from Monday, September 17, to Monday, September 24.
The South Wales Trunk Road Agent is undertaking the work on the parapets of the 400-year-old Wye Bridge which was built in stone between 1615 and 1617.
It could be a foretaste of the disruption to come between the A40 dual carriageway at the town end of the bridge, linking the Midlands and South Wales, and the Forest and the Wye Valley.
Work is set to start next spring on creating a slip road on the A40 for traffic wanting to cross the river, which is likely to cause long delays, particularly during the rush hour.